drm/mgag200: removed optional dummy encoder mode_fixup function.

mode_fixup function for encoder drivers became optional with patch
http://patchwork.freedesktop.org/patch/msgid/1455106522-32307-1-git-send-email-palminha@synopsys.com

This patch set nukes all the dummy mode_fixup implementations.

(made on top of Daniel topic/drm-misc branch)
Signed-off-by: Carlos Palminha <palminha@synopsys.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/c5852d59a8890c3570ce97d16c0714a71eb61651.1455540137.git.palminha@synopsys.com

drivers/gpu/drm/mgag200/mgag200_mode.c

@@ -1479,13 +1479,6 @@ void mga_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
  * These functions are analagous to those in the CRTC code, but are intended
  * to handle any encoder-specific limitations
  */
-static bool mga_encoder_mode_fixup(struct drm_encoder *encoder,
-				   const struct drm_display_mode *mode,
-				   struct drm_display_mode *adjusted_mode)
-{
-	return true;
-}
-
 static void mga_encoder_mode_set(struct drm_encoder *encoder,
 				struct drm_display_mode *mode,
 				struct drm_display_mode *adjusted_mode)
@@ -1515,7 +1508,6 @@ static void mga_encoder_destroy(struct drm_encoder *encoder)
 
 static const struct drm_encoder_helper_funcs mga_encoder_helper_funcs = {
 	.dpms = mga_encoder_dpms,
-	.mode_fixup = mga_encoder_mode_fixup,
 	.mode_set = mga_encoder_mode_set,
 	.prepare = mga_encoder_prepare,
 	.commit = mga_encoder_commit,