drm/sti: Drop of_gpio header

This driver includes the deprecated OF GPIO header <linux/of_gpio.h>
yet fail to use symbols from it, so drop this include.

Cc: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Acked-by: Alain Volmat <avolmat@me.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220812205746.609107-5-mairacanal@riseup.net

drivers/gpu/drm/sti/sti_dvo.c

@@ -8,7 +8,7 @@
 #include <linux/component.h>
 #include <linux/debugfs.h>
 #include <linux/module.h>
-#include <linux/of_gpio.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
 
 #include <drm/drm_atomic_helper.h>