ata: sata_mv: Fix misnaming of 'mv_bmdma_stop()'

ata: sata_mv: Fix misnaming of 'mv_bmdma_stop()'

Fixes the following W=1 kernel build warning(s):

 drivers/ata/sata_mv.c:1929: warning: expecting prototype for mv_bmdma_stop(). Prototype was for mv_bmdma_stop_ap() instead

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mark Lord <mlord@pobox.com>
Cc: ALWAYS copy <linux-ide@vger.kernel.org>
Cc: linux-ide@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210318085150.3131936-14-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>