feat(rdfremont): add support for RD-Fremont

Add the required source and header files to support RD-Fremont.
Additionally, create a makefile for building the platform.

Co-developed-by: Harry Moulton <harry.moulton@arm.com>
Signed-off-by: Harry Moulton <harry.moulton@arm.com>
Signed-off-by: Rohit Mathew <rohit.mathew@arm.com>
Change-Id: I03b6913b08d488c86a5f4638ef6cd8b0f5c43a9a
13 files changed