drm/shmobile: Enable compilation on all ARM platforms

This is required to support multi-arch kernels.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

drivers/gpu/drm/shmobile/Kconfig

 config DRM_SHMOBILE
 	tristate "DRM Support for SH Mobile"
-	depends on DRM && (SUPERH || ARCH_SHMOBILE)
+	depends on DRM && (ARM || SUPERH)
 	select DRM_KMS_HELPER
 	select DRM_KMS_CMA_HELPER
 	select DRM_GEM_CMA_HELPER