ata: ep93xx: use dmaengine_prep_slave_sg api instead of internal callback

it is better to use generic api instead of calling an internal callback
like channel->device->device_prep_slave_sg().

Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
1 file changed