ACPI: PM: Print debug messages when enabling GPEs for wakeup

In sufficiently complicated GPE configurations it is hard to
determine which GPE could be the source of system wakeup from a sleep
state, so make __acpi_device_wakeup_enable() print that information
to the kernel log if debugging is enabled.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/device_pm.c

@@ -728,6 +728,9 @@ static int __acpi_device_wakeup_enable(struct acpi_device *adev,
 		goto out;
 	}
 
+	acpi_handle_debug(adev->handle, "GPE%2X enabled for wakeup\n",
+			  (unsigned int)wakeup->gpe_number);
+
 inc:
 	wakeup->enable_count++;