usb-storage: Add support for FL_ALWAYS_SYNC flag in the UAS driver

The ALWAYS_SYNC flag is currently honored by the usb-storage driver but not UAS
and is required to work around devices that become unstable upon being
queried for cache. This code is taken straight from:
drivers/usb/storage/scsiglue.c:284
Signed-off-by: NAlexander Kappner <agk@godking.net>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Acked-by: NOliver Neukum <oneukum@suse.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/storage/uas.c

@@ -836,6 +836,12 @@ static int uas_slave_configure(struct scsi_device *sdev)
 	if (devinfo->flags & US_FL_BROKEN_FUA)
 		sdev->broken_fua = 1;
 
+	/* UAS also needs to support FL_ALWAYS_SYNC */
+	if (devinfo->flags & US_FL_ALWAYS_SYNC) {
+		sdev->skip_ms_page_3f = 1;
+		sdev->skip_ms_page_8 = 1;
+		sdev->wce_default_on = 1;
+	}
 	scsi_change_queue_depth(sdev, devinfo->qdepth - 2);
 	return 0;
 }