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
diff --git a/docs/about/maintainers.rst b/docs/about/maintainers.rst
index 725e96b..07f258c 100644
--- a/docs/about/maintainers.rst
+++ b/docs/about/maintainers.rst
@@ -415,13 +415,13 @@
 :|F|: plat/arm/board/rdv1mc/
 :|F|: plat/arm/board/sgi575/
 
-Arm Total Compute(tc0) platform port
+Arm Total Compute platform port
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 :|M|: Arunachalam Ganapathy <arunachalam.ganapathy@arm.com>
 :|G|: `arugan02`_
 :|M|: Usama Arif <usama.arif@arm.com>
 :|G|: `uarif1`_
-:|F|: plat/arm/board/tc0
+:|F|: plat/arm/board/tc
 
 HiSilicon HiKey and HiKey960 platform ports
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^