HID: wiimote: lock DRM mode during debugfs overwrite

If we write a DRM mode via debugfs, we shouldn't allow normal operations
to overwrite this DRM mode. This is important if we want to debug
3rd-party devices and we want to see what data is sent on each mode.

If we write NULL/0 as DRM, the lock is removed again so the best matching
DRM is chosen by wiimote core.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-wiimote.h b/drivers/hid/hid-wiimote.h
index 3a8bdb9..9f857c1 100644
--- a/drivers/hid/hid-wiimote.h
+++ b/drivers/hid/hid-wiimote.h
@@ -43,6 +43,7 @@
 #define WIIPROTO_FLAG_MP_USED		0x1000
 #define WIIPROTO_FLAG_MP_ACTIVE		0x2000
 #define WIIPROTO_FLAG_EXITING		0x4000
+#define WIIPROTO_FLAG_DRM_LOCKED	0x8000
 
 #define WIIPROTO_FLAGS_LEDS (WIIPROTO_FLAG_LED1 | WIIPROTO_FLAG_LED2 | \
 					WIIPROTO_FLAG_LED3 | WIIPROTO_FLAG_LED4)