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/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a897646..1150444 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1074,6 +1074,9 @@
 
 			* [no]ncq: Turn on or off NCQ.
 
+			* nohrst, nosrst, norst: suppress hard, soft
+                          and both resets.
+
 			If there are multiple matching configurations changing
 			the same attribute, the last one is used.