mem_protect: Add mem_protect API

This patch adds the generic code that links the psci smc handler
with the platform function that implements the mem_protect and
mem_check_range functionalities. These functions are  optional
APIs added in PSCI v1.1 (ARM DEN022D).

Change-Id: I3bac1307a5ce2c7a196ace76db8317e8d8c8bb3f
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/lib/psci/psci_lib.mk b/lib/psci/psci_lib.mk
index 29080db..1d4aac4 100644
--- a/lib/psci/psci_lib.mk
+++ b/lib/psci/psci_lib.mk
@@ -17,6 +17,7 @@
 				lib/psci/psci_main.c			\
 				lib/psci/psci_setup.c			\
 				lib/psci/psci_system_off.c		\
+				lib/psci/psci_mem_protect.c		\
 				lib/psci/${ARCH}/psci_helpers.S
 
 ifeq (${ARCH}, aarch64)