drm/arc: make fbdev support really optional

Currently enabling ARC DRM support automatically pulls in
fbdev dependency. However this dep is unnecessary since
DRM core already handles this for us (DRM_FBDEV_EMULATION).
Signed-off-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1468586897-32298-2-git-send-email-tjakobi@math.uni-bielefeld.de

drivers/gpu/drm/arc/Kconfig

@@ -2,7 +2,6 @@ config DRM_ARCPGU
 	tristate "ARC PGU"
 	depends on DRM && OF
 	select DRM_KMS_CMA_HELPER
-	select DRM_KMS_FB_HELPER
 	select DRM_KMS_HELPER
 	help
 	  Choose this option if you have an ARC PGU controller.