drm/msm/mdp4: Drop unused GPIO include

This file is not using any symbols from <linux/gpio.h> so just
drop this include.

Cc: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <sean@poorly.run>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c

@@ -5,8 +5,6 @@
  * Author: Vinay Simha <vinaysimha@inforcecomputing.com>
  */
 
-#include <linux/gpio.h>
-
 #include "mdp4_kms.h"
 
 struct mdp4_lvds_connector {