feat(lib/realm): use DZ ZVA instruction for granule zeroing

This patch modifies granule_memzero_mapped() function
by replacing calls to memset() with DC ZVA instructions
executed in a loop.

Change-Id: I8dc012d337032ddcd78e22323dcc07089113e5ee
Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
9 files changed