acer-wireless: send an EV_SYN/SYN_REPORT between state changes

Sending the switch state change twice within the same frame is invalid
evdev protocol and only works if the client handles keys immediately as
well. Processing events immediately is incorrect, it forces a fake
order of events that does not exist on the device.

Recent versions of libinput changed to only process the device state and
SYN_REPORT time, so now the key event is lost.

Same fix as 'commit <bff5bf9d> ("platform/x86: asus-wireless: send
an EV_SYN/SYN_REPORT between state changes")'
Signed-off-by: Daniel Drake <drake@endlessos.org>
Signed-off-by: Chris Chiu <chiu@endlessos.org>
Link: https://lore.kernel.org/r/20201207064322.13992-1-chiu@endlessos.orgSigned-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/acer-wireless.c

@@ -28,6 +28,7 @@ static void acer_wireless_notify(struct acpi_device *adev, u32 event)
 		return;
 	}
 	input_report_key(idev, KEY_RFKILL, 1);
+	input_sync(idev);
 	input_report_key(idev, KEY_RFKILL, 0);
 	input_sync(idev);
 }