feat(plat/arm): Introduce TC1 platform

This renames tc0 platform folder and files to tc, and introduces
TARGET_PLATFORM variable to account for the differences between
TC0 and TC1.

Signed-off-by: Usama Arif <usama.arif@arm.com>
Change-Id: I5b4a83f3453afd12542267091b3edab4c139c5cd
22 files changed