NRF52 : Fix UART RTS initialization

The preprocessor based macro check #if evaluates all
enums as 0 and hence the code does not get compiled.
Since move this to a runtime check where the pin variable
can be correctly evaluated.

Delete mbed_overrides.c as it has a target specific mbed_sdk_init() to
resolve linking problem.

This is a follow on patch to:
#8046

Author: Naveen Kaje

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/TARGET_MCU_NRF52832/TARGET_DELTA_DFBM_NQ620/PinNames.h

@@ -141,6 +141,8 @@ typedef enum {
     USBRX = RX_PIN_NUMBER,
     STDIO_UART_TX = TX_PIN_NUMBER,
     STDIO_UART_RX = RX_PIN_NUMBER,
+    STDIO_UART_CTS = CTS_PIN_NUMBER,
+    STDIO_UART_RTS = RTS_PIN_NUMBER,
 
     SPI_PSELMOSI0 = p23,
     SPI_PSELMISO0 = p24,

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/TARGET_MCU_NRF52832/TARGET_DELTA_DFBM_NQ620/mbed_overrides.c

@@ -121,6 +121,8 @@ typedef enum {
     RTS_PIN_NUMBER = p31,
     STDIO_UART_TX = TX_PIN_NUMBER,
     STDIO_UART_RX = RX_PIN_NUMBER,
+    STDIO_UART_CTS = CTS_PIN_NUMBER,
+    STDIO_UART_RTS = RTS_PIN_NUMBER,
 
     I2C_SDA = p2,
     I2C_SCL = p3,

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/TARGET_MCU_NRF52832/TARGET_MTB_UBLOX_NINA_B1/PinNames.h

@@ -132,6 +132,8 @@ typedef enum {
     RTS_PIN_NUMBER = p2,
     STDIO_UART_TX = TX_PIN_NUMBER,
     STDIO_UART_RX = RX_PIN_NUMBER,
+    STDIO_UART_CTS = CTS_PIN_NUMBER,
+    STDIO_UART_RTS = RTS_PIN_NUMBER,
 
     // mBed interface Pins
     USBTX = TX_PIN_NUMBER,

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/TARGET_MCU_NRF52832/TARGET_RBLAB_BLENANO2/PinNames.h

@@ -86,6 +86,8 @@ typedef enum {
     RTS_PIN_NUMBER = p31,
     STDIO_UART_TX = TX_PIN_NUMBER,
     STDIO_UART_RX = RX_PIN_NUMBER,
+    STDIO_UART_CTS = CTS_PIN_NUMBER,
+    STDIO_UART_RTS = RTS_PIN_NUMBER,
 
     I2C_SDA0 = p2,
     I2C_SCL0 = p3,

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/TARGET_MCU_NRF52832/TARGET_UBLOX_EVA_NINA/PinNames.h

@@ -113,12 +113,13 @@ void nrf_reloc_vector_table(void)
 #endif
 }
 
-#if (STDIO_UART_RTS != NC)
+
 void mbed_sdk_init(void)
 {
-	gpio_t rts;
-	gpio_init_out(&rts, STDIO_UART_RTS);
-	/* Set STDIO_UART_RTS as gpio driven low */
-	gpio_write(&rts, 0);
+	if (STDIO_UART_RTS != NC) {
+		gpio_t rts;
+		gpio_init_out(&rts, STDIO_UART_RTS);
+		/* Set STDIO_UART_RTS as gpio driven low */
+		gpio_write(&rts, 0);
+	}
 }
-#endif