feat(rme): add GPT Library

This patch introduces the Granule Protection Table (GPT)
library code. This implementation will be updated later to
be more flexible, as the current implementation is very rigid.

Signed-off-by: Zelalem Aweke <zelalem.aweke@arm.com>
Change-Id: I3af824a28c6e9a5d36459c0c51d2d9bebfba1505
diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index ce0f69b..5927fb1 100644
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -112,7 +112,10 @@
 endif
 
 ifeq (${ENABLE_RME},1)
-BL31_SOURCES		+=	${RMMD_SOURCES}
+include lib/gpt/gpt.mk
+
+BL31_SOURCES		+=	${GPT_LIB_SRCS}					\
+				${RMMD_SOURCES}
 endif
 
 BL31_LINKERFILE		:=	bl31/bl31.ld.S