drm/udl: make fbdev support really optional

Currently enabling USB DisplayLink 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/1468586897-32298-17-git-send-email-tjakobi@math.uni-bielefeld.de

drivers/gpu/drm/udl/Kconfig

@@ -4,12 +4,7 @@ config DRM_UDL
 	depends on USB_SUPPORT
 	depends on USB_ARCH_HAS_HCD
 	select USB
-	select FB_SYS_FILLRECT
-	select FB_SYS_COPYAREA
-	select FB_SYS_IMAGEBLIT
-	select FB_DEFERRED_IO
 	select DRM_KMS_HELPER
-        select DRM_KMS_FB_HELPER
 	help
 	  This is a KMS driver for the USB displaylink video adapters.
           Say M/Y to add support for these devices via drm/kms interfaces.