Fix(c2_bt): FG: Update doc for uart setup

Change C2 pins so that devkit can be easily used.

Author: mantriyogesh

esp_hosted_fg/docs/Linux_based_host/UART_setup.md

@@ -2,10 +2,10 @@
 
 | Supported Chipsets | ESP32 | ESP32-C2 | ESP32-C3 | ESP32-S3 | ESP32-C6 | ESP32-C5 | ESP32-S2 |
 | ------------------ | :---: | :------: | :------: | :------: | :------: | :------: | :------: |
-| 4 line UART        | Y     | N        | Y        | Y        | N        | N        | Y        |
-| 2 line UART        | N     | Y        | N        | N        | Y        | Y        | N        |
+| 4 line UART        | T     | NT        | T        | T        | NT        | NT        | T        |
+| 2 line UART        | NT     | T        | NT        | NT        | T        | T        | NT        |
 
-Y - **Tested**, N - **Not Tested**
+T - **Tested**, NT - **Not Tested**
 
 In this section, ESP chipset provides a way to run Bluetooth/BLE over UART interface.
 Please connect ESP peripheral to Raspberry-Pi with jumper cables (preferably PCB) as mentioned below.
@@ -28,6 +28,12 @@ Raspberry-Pi pinout can be found [here!](https://pinout.xyz/pinout/uart)
 
 #### Four Line UART setup
 
+> [!NOTE]
+>
+> For UART protocol
+> - Host TX is to be connected to slave RX & vice versa.
+> - Host CTS is to be connected to slave RTS & vice versa.
+
 | Raspberry-Pi Pin Function | Raspberry-Pi Pin | ESP32 | ESP32-S3 | ESP32-C3 | ESP32 Pin Function |
 |:-------:|:--------:|:---------:|:--------:|:--------:|:--------:|
 | RX | 10 | IO5 | IO17 | IO5 | TX |
@@ -41,15 +47,21 @@ Sample SPI+UART setup image looks like:
 
 #### Two Line UART setup
 
+> [!NOTE]
+>
+> For UART protocol, Host TX is connected to slave RX & vice versa.
 
 | Raspberry-Pi Pin Function | Raspberry-Pi Pin | ESP32-C2 | ESP32-C5 | ESP32-C6 | ESP Function |
 |:-------:|:--------:|:---------:|:--------:|:--------:|:--------:|
-| TX | 8  | IO5  | IO5  | IO5  | TX |
-| RX | 10 | IO18 | IO23 | IO12 | RX |
-
-Note:
-- ESP32-C2 only
-	- Although, `HCI with UART` is supported on `ESP32-C2`, `Wi-Fi + Bluetooth` (together) when used with `SPI+UART` setup, Bluetooth on UART works fine but Wi-Fi on SPI faces low throughput problem. By the time this is rectified, please use 'SPI only' i.e. `HCI over SPI` and `Wi-Fi over SPI` transport combination. In `SPI only` setup, there is no such limitation.
+| RX | 10 | IO5  | IO5  | IO5  | TX |
+| TX | 8 | IO1 | IO23 | IO12 | RX |
+
+> [ !CAUTION ]
+> - ESP32-C2 only
+>	- ESP32-C2 has much less IRAM, without PSRAM support.
+>	- With `SPI+UART` mode, i.e. Wi-Fi on SPI & BLE over UART mode, Wi-Fi on SPI faces low throughput problem when uart is loaded.
+>	- With `SPI only` mode, i.e. Wi-Fi & BLE, both, running over SPI, both, Wi-Fi and Bluetooth work smooth.
+>	- Conclusion, For `ESP32-C2`, prefer using `SPI only` mode.
 
 
 ### 1.2 Raspberry-Pi Software Setup

esp_hosted_fg/esp/esp_driver/network_adapter/main/slave_bt.c

@@ -413,9 +413,7 @@ static void init_uart_c2_c6_c5(void)
 {
 	ESP_LOGD(TAG, "Set-up BLE for ESP32-C2/C6/C5");
 
-#if defined(CONFIG_IDF_TARGET_ESP32C2)
-	ESP_LOGI(TAG, "UART Pins: Tx:%u Rx:%u", BT_TX_PIN, BT_RX_PIN);
-#elif defined(CONFIG_IDF_TARGET_ESP32C6) || defined(CONFIG_IDF_TARGET_ESP32C5)
+#if defined(CONFIG_IDF_TARGET_ESP32C2) || defined(CONFIG_IDF_TARGET_ESP32C6) || defined(CONFIG_IDF_TARGET_ESP32C5)
 	//ESP_ERROR_CHECK( uart_set_pin(BLUETOOTH_UART, BT_TX_PIN,
 	//  BT_RX_PIN, BT_RTS_PIN, BT_CTS_PIN) );
 	ESP_LOGI(TAG, "UART Pins: Tx:%u Rx:%u", BT_TX_PIN, BT_RX_PIN);

esp_hosted_fg/esp/esp_driver/network_adapter/main/slave_bt.h

@@ -89,14 +89,7 @@
     #define BT_RTS_PIN         19
     #define BT_CTS_PIN         23
 
-  #elif defined(CONFIG_IDF_TARGET_ESP32C2)
-
-      #define BT_TX_PIN         5
-      #define BT_RX_PIN         18
-      //#define BT_RTS_PIN        9
-      //#define BT_CTS_PIN        8
-
-  #elif defined(CONFIG_IDF_TARGET_ESP32C6) || defined(CONFIG_IDF_TARGET_ESP32C5)
+  #elif defined(CONFIG_IDF_TARGET_ESP32C2) || defined(CONFIG_IDF_TARGET_ESP32C6) || defined(CONFIG_IDF_TARGET_ESP32C5)
 
       #define BT_TX_PIN         CONFIG_BT_LE_HCI_UART_TX_PIN
       #define BT_RX_PIN         CONFIG_BT_LE_HCI_UART_RX_PIN