Use swap() in order to make code cleaner. Issue found by coccinelle.
Reported-by: NZeal Robot <zealci@zte.com.cn>
Signed-off-by: NChangcheng Deng <deng.changcheng@zte.com.cn>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>