Plat: Corstone-1000: Add MM communication buffer configs to CMake

Two variables are added into the Corstone-1000 platform
CMake file so the MM communication buffer address and
the page count can be configured.

Change-Id: I6bbdc90231b0417d4318d6709568113ab1f2c8ce
Signed-off-by: Michael Safwat <michael.safwat@arm.com>
1 file changed