dmaengine: mv_xor_v2 : Move spin_lock_bh() to spin_lock()

It is unnecessary to call spin_lock_bh() for that you are already
in a tasklet.

Signed-off-by: Yunbo Yu <yuyunbo519@gmail.com>
Link: https://lore.kernel.org/r/20220420122754.148359-1-yuyunbo519@gmail.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>