libata: implement no[hs]rst force params

Implement force params nohrst, nosrst and norst.  This is to work
around reset related problems and ease debugging.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 06b8033..5340d4c 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -163,6 +163,7 @@
 	ATA_DEV_NONE		= 9,	/* no device */
 
 	/* struct ata_link flags */
+	ATA_LFLAG_NO_HRST	= (1 << 1), /* avoid hardreset */
 	ATA_LFLAG_NO_SRST	= (1 << 2), /* avoid softreset */
 	ATA_LFLAG_ASSUME_ATA	= (1 << 3), /* assume ATA class */
 	ATA_LFLAG_ASSUME_SEMB	= (1 << 4), /* assume SEMB class */