feat(ff-a): add v1.2 fields to RXTX header

Add the new fields introduced in v1.2 to the partition message header.

Change-Id: Id17c7aca34d5bfa555ece3ad9d928f577ddeeceb
Signed-off-by: Karl Meakin <karl.meakin@arm.com>
diff --git a/src/api.c b/src/api.c
index 6ff31ba..5754376 100644
--- a/src/api.c
+++ b/src/api.c
@@ -2048,7 +2048,7 @@
 	 * unsafe memory which could be 'corrupted' between safety checks and
 	 * final buffer copy.
 	 */
-	if (!memcpy_trapped(&header, FFA_RXTX_HEADER_SIZE, sender_tx_buffer,
+	if (!memcpy_trapped(&header, sizeof(header), sender_tx_buffer,
 			    FFA_RXTX_HEADER_SIZE)) {
 		dlog_error(
 			"%s: Failed to copy message from sender's(%x) TX "