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

 drivers/ata/ata_generic.c:164: warning: expecting prototype for ata_generic_init(). Prototype was for ata_generic_init_one() instead

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andre Hedrick <andre@linux-ide.org>
Cc: Hat Inc <alan@redhat.com>
Cc: linux-ide@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210318085150.3131936-11-lee.jones@linaro.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>