mei: speed up the power down flow

When mei driver is powering down due to suspend or shutdown
it will iterate over the mei client bus and disconnect
each client device attached in turn.
The power down flow consist of the link rest, which causes all clients
get disconnected at once, hence the individual disconnection
can be omitted and significantly reduce power down flow.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hw-txe.c

@@ -1127,7 +1127,9 @@ irqreturn_t mei_txe_irq_thread_handler(int irq, void *dev_id)
 	if (test_and_clear_bit(TXE_INTR_OUT_DB_BIT, &hw->intr_cause)) {
 		/* Read from TXE */
 		rets = mei_irq_read_handler(dev, &cmpl_list, &slots);
-		if (rets && dev->dev_state != MEI_DEV_RESETTING) {
+		if (rets &&
+		    (dev->dev_state != MEI_DEV_RESETTING ||
+		     dev->dev_state != MEI_DEV_POWER_DOWN)) {
 			dev_err(dev->dev,
 				"mei_irq_read_handler ret = %d.\n", rets);