sata: wait for device updating signature to host

The driver need wait for the device updating signature to host.
If we don't wait for it, the driver can not detect the device(disk)
when the system powers up.

Signed-off-by: Dave Liu <daveliu@freescale.com>

drivers/block/fsl_sata.c

@@ -248,6 +248,10 @@ int init_sata(int dev)
 	else
 		printf("       %s ", sata->name);
 
+	/* Wait PHY RDY signal changed for 500ms */
+	ata_wait_register(&reg->hstatus, HSTATUS_PHY_RDY,
+			  HSTATUS_PHY_RDY, 500);
+
 	/* Check PHYRDY */
 	val32 = in_le32(&reg->hstatus);
 	if (val32 & HSTATUS_PHY_RDY) {
@@ -258,6 +262,10 @@ int init_sata(int dev)
 		return -1;
 	}
 
+	/* Wait for signature updated, which is 1st D2H */
+	ata_wait_register(&reg->hstatus, HSTATUS_SIGNATURE,
+			  HSTATUS_SIGNATURE, 10000);
+
 	if (val32 & HSTATUS_SIGNATURE) {
 		sig = in_le32(&reg->sig);
 		debug("Signature updated, the sig =%08x\n\r", sig);