dell-laptop: Only enable rfkill functionality on laptops with a hw killswitch

All my testing has been on laptops with a hw killswitch, so to be on the
safe side disable rfkill functionality on models without a hw killswitch for
now. Once we gather some feedback on laptops without a hw killswitch this
decision maybe reconsidered.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

drivers/platform/x86/dell-laptop.c

@@ -580,11 +580,18 @@ static int __init dell_setup_rfkill(void)
 	buffer->input[0] = 0x2;
 	dell_send_request(buffer, 17, 11);
 	hwswitch_state = buffer->output[1];
-	/* If there is no hwswitch, then clear all hw-controlled bits */
-	if (!(status & BIT(0)))
-		hwswitch_state &= ~7;
 	release_buffer();
 
+	if (!(status & BIT(0))) {
+		if (force_rfkill) {
+			/* No hwsitch, clear all hw-controlled bits */
+			hwswitch_state &= ~7;
+		} else {
+			/* rfkill is only tested on laptops with a hwswitch */
+			return 0;
+		}
+	}
+
 	if ((status & (1<<2|1<<8)) == (1<<2|1<<8)) {
 		wifi_rfkill = rfkill_alloc("dell-wifi", &platform_device->dev,
 					   RFKILL_TYPE_WLAN,