libata: detect Device Attention support

Add a new flag ATA_DFLAG_DA to indicate that device supports "Device
Attention".

Acked-by: Aaron Lu <aaron.lu@amd.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 888feef..cc22b943 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -161,6 +161,8 @@
 	ATA_DFLAG_DETACH	= (1 << 24),
 	ATA_DFLAG_DETACHED	= (1 << 25),
 
+	ATA_DFLAG_DA		= (1 << 26), /* device supports Device Attention */
+
 	ATA_DEV_UNKNOWN		= 0,	/* unknown device */
 	ATA_DEV_ATA		= 1,	/* ATA device */
 	ATA_DEV_ATA_UNSUP	= 2,	/* ATA device (unsupported) */