libata: add SATA PMP revision information for spec 1.2

This small patch is just adding the information for PMP spec 1.2

Signed-off-by: Shane Huang <shane.huang@amd.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c
index 619f2c3..51f0ffb 100644
--- a/drivers/ata/libata-pmp.c
+++ b/drivers/ata/libata-pmp.c
@@ -221,6 +221,8 @@
 {
 	u32 rev = gscr[SATA_PMP_GSCR_REV];
 
+	if (rev & (1 << 3))
+		return "1.2";
 	if (rev & (1 << 2))
 		return "1.1";
 	if (rev & (1 << 1))