platform: nordic_nrf: restore TFM_DRIVER_STDIO's default value

If NRF_SECURE_UART_INSTANCE is not defined (which it is only in
NCS), bring back the default behavior of assigning Driver_USART1
to TFM_DRIVER_STDIO.

This fixes the issue of undefined references to Driver_USART0
in non-NCS environments that was introduced by
commit 2ed1f3f/

Signed-off-by: Tomi Fontanilles <[email protected]>
Change-Id: I0b51a957ffc41c593b4cecd21a72b801ef90f656
(cherry picked from commit 66dc44b)

Author: Vge0rge

platform/ext/target/nordic_nrf/common/core/target_cfg.h

@@ -35,7 +35,9 @@
 #include "tfm_plat_defs.h"
 #include "region_defs.h"
 
-#if NRF_SECURE_UART_INSTANCE == 0
+#ifndef NRF_SECURE_UART_INSTANCE
+#define TFM_DRIVER_STDIO    Driver_USART1
+#elif NRF_SECURE_UART_INSTANCE == 0
 #define TFM_DRIVER_STDIO    Driver_USART0
 #elif NRF_SECURE_UART_INSTANCE == 1
 #define TFM_DRIVER_STDIO    Driver_USART1