mei: me: add pg exit and entry flow commands

For power gating entry we write hbm pg entry request command and
then we set pg register
For power gating exit we clear pg register and wait for exit request
hbm command.

Exit power gating request might also be initiated by the firmware
w/o explicit driver request

The power gating state is tracked by pg_state member of me_hw

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-me.h

@@ -31,12 +31,16 @@ struct mei_me_hw {
 	 */
 	u32 host_hw_state;
 	u32 me_hw_state;
+	enum mei_pg_state pg_state;
 };
 
 #define to_me_hw(dev) (struct mei_me_hw *)((dev)->hw)
 
 struct mei_device *mei_me_dev_init(struct pci_dev *pdev);
 
+int mei_me_pg_set_sync(struct mei_device *dev);
+int mei_me_pg_unset_sync(struct mei_device *dev);
+
 irqreturn_t mei_me_irq_quick_handler(int irq, void *dev_id);
 irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id);