mei: implement power gating isolation hbm layer

Add send message functions and receive dispatch stubs
for power gating isolation hbm protocol.

The protocol consist of requests for entering and exiting
the power gating isolation state and their responses.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 94a5167..4d4c041 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -371,6 +371,7 @@
 	 * waiting queue for receive message from FW
 	 */
 	wait_queue_head_t wait_hw_ready;
+	wait_queue_head_t wait_pg;
 	wait_queue_head_t wait_recvd_msg;
 	wait_queue_head_t wait_stop_wd;