btrfs: use appropriate define for the fsid

Though BTRFS_FSID_SIZE and BTRFS_UUID_SIZE are of the same size, we
should use the matching constant for the fsid buffer.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 7d65d98..7b9aabc 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -1732,7 +1732,7 @@ static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 	num_pages = state->metablock_size >> PAGE_SHIFT;
 	h = (struct btrfs_header *)datav[0];
 
-	if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
+	if (memcmp(h->fsid, fs_info->fsid, BTRFS_FSID_SIZE))
 		return 1;
 
 	for (i = 0; i < num_pages; i++) {