Platform: Refactor generic USART device usage

Add an extra config layer in cmsis_driver_config.h to platform
specifically select the UART device to be used with the required
security domain for TFM core and Non-Secure application separately.
This way the platform independent TFM core UART usage becomes
completely platform agnostic, using a generic CMSIS UART device.

Change-Id: I3e957fcc4df6d041fef2f350c2d7b329a368a220
Signed-off-by: Gabor Kertesz <gabor.kertesz@arm.com>
diff --git a/platform/ext/common/uart_stdout.h b/platform/ext/common/uart_stdout.h
index e9afe03..063ae05 100644
--- a/platform/ext/common/uart_stdout.h
+++ b/platform/ext/common/uart_stdout.h
@@ -1,5 +1,5 @@
 /*

- * Copyright (c) 2017 ARM Limited

+ * Copyright (c) 2017-2018 ARM Limited

  *

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

@@ -30,12 +30,10 @@
 };

 

 /**

- * \brief Initializes the UART.

+ * \brief Initializes the STDIO.

  *

- * \param[in] uchan UART channel

- *                  to use, 0 or 1.

  */

-void uart_init(enum uart_channel uchan);

+void stdio_init(void);

 

 /**

  * \brief Puts a character in the UART.