AHCI: use ATA_BUSY

ahci_hardreset() and ahci_p5wdh_hardreset() use bare numbers for the
BSY bit of the ATA status register, despite it's #define'd in
<linux/ata.h>.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index da45325..8db82d3 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -583,7 +583,7 @@
 
 	/* clear D2H reception area to properly wait for D2H FIS */
 	ata_tf_init(link->device, &tf);
-	tf.command = 0x80;
+	tf.command = ATA_BUSY;
 	ata_tf_to_fis(&tf, 0, 0, d2h_fis);
 
 	rc = sata_link_hardreset(link, sata_ehc_deb_timing(&link->eh_context),