drm/mtk: Remove impossible internal error

We cannot create a framebuffer with no objects, so there's no point
testing for it.

v2: Remove the error entirely. (Sean, CK, Thierry)
Signed-off-by: Daniel Stone <daniels@collabora.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: CK Hu <ck.hu@mediatek.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20180518134705.12533-1-daniels@collabora.com

drivers/gpu/drm/mediatek/mtk_drm_plane.c

@@ -95,11 +95,6 @@ static int mtk_plane_atomic_check(struct drm_plane *plane,
 	if (!fb)
 		return 0;
 
-	if (!mtk_fb_get_gem_obj(fb)) {
-		DRM_DEBUG_KMS("buffer is null\n");
-		return -EFAULT;
-	}
-
 	if (!state->crtc)
 		return 0;