libata: add @ap to ata_wait_register() and introduce ata_msleep()

Add optional @ap argument to ata_wait_register() and replace msleep()
calls with ata_msleep() which take optional @ap in addition to the
duration.  These will be used to implement EH exclusion.

This patch doesn't cause any behavior difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/pata_bf54x.c

@@ -1046,7 +1046,7 @@ static void bfin_bus_post_reset(struct ata_port *ap, unsigned int devmask)
 			dev1 = 0;
 			break;
 		}
-		msleep(50);	/* give drive a breather */
+		ata_msleep(ap, 50);	/* give drive a breather */
 	}
 	if (dev1)
 		ata_sff_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);
@@ -1087,7 +1087,7 @@ static unsigned int bfin_bus_softreset(struct ata_port *ap,
 	 *
 	 * Old drivers/ide uses the 2mS rule and then waits for ready
 	 */
-	msleep(150);
+	ata_msleep(ap, 150);
 
 	/* Before we perform post reset processing we want to see if
 	 * the bus shows 0xFF because the odd clown forgets the D7