drm/arm: Make ARM devices menu depend on DRM

Otherwise if CONFIG_DRM is disabled, menuconfig will show an empty menu.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230703230534.997525-4-javierm@redhat.com

drivers/gpu/drm/arm/Kconfig

 # SPDX-License-Identifier: GPL-2.0
 menu "ARM devices"
+	depends on DRM
 
 config DRM_HDLCD
 	tristate "ARM HDLCD"