drm/mgag200: make fbdev support really optional

Currently enabling MGA G200 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/1468586897-32298-5-git-send-email-tjakobi@math.uni-bielefeld.de

drivers/gpu/drm/mgag200/Kconfig

 config DRM_MGAG200
 	tristate "Kernel modesetting driver for MGA G200 server engines"
 	depends on DRM && PCI
-	select FB_SYS_FILLRECT
-	select FB_SYS_COPYAREA
-	select FB_SYS_IMAGEBLIT
 	select DRM_KMS_HELPER
-	select DRM_KMS_FB_HELPER
 	select DRM_TTM
 	help
 	 This is a KMS driver for the MGA G200 server chips, it