HID: wacom_sys: Demote kernel-doc abuse

Fixes the following W=1 kernel build warning(s):

 drivers/hid/wacom_sys.c:1505: warning: Function parameter or member 'wacom' not described in 'wacom_led_next'
 drivers/hid/wacom_sys.c:1505: warning: Function parameter or member 'cur' not described in 'wacom_led_next'

Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: linux-input@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

drivers/hid/wacom_sys.c

@@ -1495,7 +1495,7 @@ struct wacom_led *wacom_led_find(struct wacom *wacom, unsigned int group_id,
 	return &group->leds[id];
 }
 
-/**
+/*
  * wacom_led_next: gives the next available led with a wacom trigger.
  *
  * returns the next available struct wacom_led which has its default trigger