fix: not null uuid then return should be null

If the caller to FFA_PARTITION_INFO_GET provided
an UUID, then the returned UUID in the info descriptor
MBZ.

The `api_ffa_fill_partition_info` was not zeroing the
field, which it meant the previously used UUID
was being copied.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I210f2097300ca79770531db0a6963140c2b33760
diff --git a/src/api.c b/src/api.c
index c5c40b3..9ce1964 100644
--- a/src/api.c
+++ b/src/api.c
@@ -573,7 +573,7 @@
 				 * If the number of entries surpasses the size
 				 * of `out_partitions`
 				 */
-				if (*entries_count > out_partitions_len) {
+				if (*entries_count >= out_partitions_len) {
 					return false;
 				}
 
@@ -585,8 +585,15 @@
 
 				api_ffa_fill_partition_info(out_partition, vm,
 							    caller_id);
+				/*
+				 * If the ABI has specified an UUID, then do not
+				 * write it
+				 */
 				if (match_any) {
 					out_partition->uuid = uuid;
+				} else {
+					out_partition->uuid =
+						(struct ffa_uuid){0};
 				}
 
 				/*