Make TF UUID RFC 4122 compliant

RFC4122 defines that fields are stored in network order (big endian),
but TF-A stores them in machine order (little endian by default in TF-A).
We cannot change the future UUIDs that are already generated, but we can store
all the bytes using arrays and modify fiptool to generate the UUIDs with
the correct byte order.

Change-Id: I97be2d3168d91f4dee7ccfafc533ea55ff33e46f
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/include/tools_share/uuid.h b/include/tools_share/uuid.h
index 6d935bd..f3ac4af 100644
--- a/include/tools_share/uuid.h
+++ b/include/tools_share/uuid.h
@@ -48,9 +48,9 @@
  * A DCE 1.1 compatible source representation of UUIDs.
  */
 struct uuid {
-	uint32_t	time_low;
-	uint16_t	time_mid;
-	uint16_t	time_hi_and_version;
+	uint8_t		time_low[4];
+	uint8_t		time_mid[2];
+	uint8_t		time_hi_and_version[2];
 	uint8_t		clock_seq_hi_and_reserved;
 	uint8_t		clock_seq_low;
 	uint8_t		node[_UUID_NODE_LEN];