ata: libata-sata: Fix function names in header comments

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

 drivers/ata/libata-sata.c:1085: warning: expecting prototype for port_alloc(). Prototype was for ata_sas_port_alloc() instead
 drivers/ata/libata-sata.c:1140: warning: expecting prototype for ata_port_stop(). Prototype was for ata_sas_port_stop() instead

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Tejun Heo <htejun@gmail.com>
Cc: linux-ide@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>