fix(rme): append realm.bin at end of tftf.bin

Currently realm.bin is appended to tftf.bin at offset of 10 MB.
This patch removes this dependency by reserving empty sections
for realm image and dependencies, in tftf binary after
all loadable sections (end of binary),
and append realm.bin at end of tftf.bin later in build process.

The patch removes the need for TFTF to map memory corresponding
to Realm payload dynamically at runtime.

Change-Id: Iead2dc62ff2965cf7bb03e61c93e76df218da973
Signed-off-by: Shruti Gupta <shruti.gupta@arm.com>
diff --git a/Makefile b/Makefile
index 4896ba9..54293b5 100644
--- a/Makefile
+++ b/Makefile
@@ -192,6 +192,7 @@
 $(eval $(call add_define,TFTF_DEFINES,NEW_TEST_SESSION))
 $(eval $(call add_define,TFTF_DEFINES,PLAT_${PLAT}))
 $(eval $(call add_define,TFTF_DEFINES,USE_NVM))
+$(eval $(call add_define,TFTF_DEFINES,ENABLE_REALM_PAYLOAD_TESTS))
 
 ################################################################################
 
@@ -606,7 +607,7 @@
 tftf: realm
 	@echo "  PACK REALM PAYLOAD"
 	$(shell dd if=$(BUILD_PLAT)/realm.bin of=$(BUILD_PLAT)/tftf.bin obs=1 \
-	seek=$(TFTF_MAX_IMAGE_SIZE))
+	oflag=append conv=notrunc)
 endif
 
 ifeq (${ARCH}-${PLAT},aarch64-fvp)
@@ -615,7 +616,7 @@
 pack_realm: realm tftf
 	@echo "  PACK REALM PAYLOAD"
 	$(shell dd if=$(BUILD_PLAT)/realm.bin of=$(BUILD_PLAT)/tftf.bin obs=1 \
-	seek=$(TFTF_MAX_IMAGE_SIZE))
+	oflag=append conv=notrunc)
 endif
 
 ifeq (${ARCH}-${PLAT},aarch64-tc)