HID: wiimote: Allow direct DRM debug access

Keep track of current drm and add new debugfs file which reads or writes the
current DRM.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-wiimote-core.c b/drivers/hid/hid-wiimote-core.c
index 2fd2f03..745667e 100644
--- a/drivers/hid/hid-wiimote-core.c
+++ b/drivers/hid/hid-wiimote-core.c
@@ -238,6 +238,7 @@
 	cmd[1] = 0;
 	cmd[2] = drm;
 
+	wdata->state.drm = drm;
 	wiiproto_keep_rumble(wdata, &cmd[1]);
 	wiimote_queue(wdata, cmd, sizeof(cmd));
 }
@@ -1141,6 +1142,7 @@
 	spin_lock_init(&wdata->state.lock);
 	init_completion(&wdata->state.ready);
 	mutex_init(&wdata->state.sync);
+	wdata->state.drm = WIIPROTO_REQ_DRM_K;
 
 	return wdata;