ide: remove action argument in ide_do_drive_cmd

ide_do_drive_cmd is called only with ide_preempt action argument. So
we can remove the action argument in ide_do_drive_cmd and ide_action_t
typedef.

This patch also includes two minor cleanups: 1) ide_do_drive_cmd
always succeeds so we don't need the return value; 2) the callers use
blk_rq_init before ide_do_drive_cmd so there is no need to initialize
rq->errors.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-cd.c

@@ -213,7 +213,7 @@ static void cdrom_queue_request_sense(ide_drive_t *drive, void *sense,
 	/* NOTE! Save the failed command in "rq->buffer" */
 	rq->buffer = (void *) failed_command;
 
-	(void) ide_do_drive_cmd(drive, rq, ide_preempt);
+	ide_do_drive_cmd(drive, rq);
 }
 
 static void cdrom_end_request(ide_drive_t *drive, int uptodate)