drm: omapdrm: Delete surplus GPIO includes

The OMAP DRM driver includes <linux/gpio.h> into the two
hdmi4.c and hdmi5.c files but does not use any symbols from
these files. Drop the includes.

Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200626220606.340937-1-linus.walleij@linaro.org

drivers/gpu/drm/omapdrm/dss/hdmi4.c

@@ -20,7 +20,6 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/clk.h>
-#include <linux/gpio.h>
 #include <linux/regulator/consumer.h>
 #include <linux/component.h>
 #include <linux/of.h>

drivers/gpu/drm/omapdrm/dss/hdmi5.c

@@ -24,7 +24,6 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/clk.h>
-#include <linux/gpio.h>
 #include <linux/regulator/consumer.h>
 #include <linux/component.h>
 #include <linux/of.h>