'error' will be initialized, so clean up the redundant initialization.

Cc: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: NShaokun Zhang <zhangshaokun@hisilicon.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>