feat(realm): assign MECID when creating realms

This change allows TFTF to assign a MECID to every realm that is
created by passing an extra parameter to the Realm creation helpers.

Signed-off-by: Juan Pablo Conde <juanpablo.conde@arm.com>
Change-Id: I89bf08011eb005d949a195b406b073955f23f5ad
diff --git a/include/common/test_helpers.h b/include/common/test_helpers.h
index 6482d6d..6a4b412 100644
--- a/include/common/test_helpers.h
+++ b/include/common/test_helpers.h
@@ -17,6 +17,9 @@
 #include <uuid_utils.h>
 #include <uuid.h>
 
+#define TEST_MECID1	(unsigned short)1
+#define TEST_MECID2	(unsigned short)2
+
 typedef struct {
 	uintptr_t addr;
 	size_t size;