feat(fvp): add plat API to validate that passed region is non-secure

Added a platform function to check passed region is within
the Non-Secure region of DRAM.

Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: Ie5808fa6a1b6e6bc99f4185fa8acc52af0d5f14d
2 files changed