StandaloneMmPkg: Fix check buffer address failed issue from TF-A

StandaloneMmPkg: Fix check buffer address failed issue from TF-A

There are two scene communicate with StandaloneMm(MM):
1 edk2 -> TF-A -> MM, communicate MM use non-secure buffer which
  specify by EFI_SECURE_PARTITION_BOOT_INFO.SpNsCommBufBase;
2 RAS scene: fiq -> TF-A -> MM, use secure buffer which
  specify by EFI_SECURE_PARTITION_BOOT_INFO.SpShareBufBase;

For now, the second scene will failed because check buffer address.
This patch add CheckBufferAddr() to support check address for secure
buffer.

Signed-off-by: Ming Huang <huangming@linux.alibaba.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>