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>

drivers/misc/mei/hw.h

@@ -69,6 +69,11 @@
 
 #define MEI_FLOW_CONTROL_CMD                0x08
 
+#define MEI_PG_ISOLATION_ENTRY_REQ_CMD      0x0a
+#define MEI_PG_ISOLATION_ENTRY_RES_CMD      0x8a
+#define MEI_PG_ISOLATION_EXIT_REQ_CMD       0x0b
+#define MEI_PG_ISOLATION_EXIT_RES_CMD       0x8b
+
 /*
  * MEI Stop Reason
  * used by hbm_host_stop_request.reason
@@ -207,6 +212,17 @@ struct hbm_props_response {
 	struct mei_client_properties client_properties;
 } __packed;
 
+/**
+ * struct hbm_power_gate - power gate request/response
+ *
+ * @hbm_cmd - bus message command header
+ * @reserved[3]
+ */
+struct hbm_power_gate {
+	u8 hbm_cmd;
+	u8 reserved[3];
+} __packed;
+
 /**
  * struct hbm_client_connect_request - connect/disconnect request
  *