xfs: Fix the return value of xfs_rtcopy_summary()

xfs_rtcopy_summary() should return the appropriate error code
instead of always returning 0. The caller of this function which is
xfs_growfs_rt_bmblock() is already handling the error.

Fixes: e94b53f ("xfs: cache last bitmap block in realtime allocator")
Signed-off-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # v6.7
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Author: Nirjhar-Roy-0211

fs/xfs/xfs_rtalloc.c

@@ -126,7 +126,7 @@ xfs_rtcopy_summary(
 	error = 0;
 out:
 	xfs_rtbuf_cache_relse(oargs);
-	return 0;
+	return error;
 }
 /*
  * Mark an extent specified by start and len allocated.