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>
15 files changed