refactor(fvp_r): tidy up platform port [1]

Following changes done:
  1. Remove "fvp_r" specific check from bl1.mk
  2. Override BL1_SOURCES in fvp_r platform.mk
  3. Regroup source files
  4. Remove platform specific change from arm_common

Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I74d0b1f317853ab1333744d8da5c59f937789547
4 files changed