examples: Replacing MDH with CMSIS Driver APIs

- Modify all the needed files to use CMSIS Driver APIs
(SAI, USART, Eth Netxduo) and Shim layers instead of using MDH
which is to be deprecated.

- Modify linker configuration cmake files to support only
ARMClang as GCC is not supported yet in total solutions.

Signed-off-by: Ahmed.Ismail <Ahmed.Ismail@arm.com>