aha1542: Call wait_mask from aha1542_out

aha1542_out call is always followed by wait_mask.
Move the call into aha1542_out to simplify code.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>