ACPI / sleep: clean up compiler warning about uninitialized field

Initialize pwr_btn_status as disabled which (a) makes sure it is
in a proper state to start, and (b) cleans up a compiler warning
about an uninitialized variable.

Signed-off-by: Al Stone <al.stone@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/sleep.c

@@ -525,7 +525,7 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 	 * generate wakeup events.
 	 */
 	if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3)) {
-		acpi_event_status pwr_btn_status;
+		acpi_event_status pwr_btn_status = ACPI_EVENT_FLAG_DISABLED;
 
 		acpi_get_event_status(ACPI_EVENT_POWER_BUTTON, &pwr_btn_status);