drm/omapdrm: Remove unused struct csc_coef_rgb2yuv

After commit 64ff1891, struct csc_coef_rgb2yuv is not used any more
and can be removed as well.

Fixes: 64ff1891 ("drm/omap: Enable COLOR_ENCODING and COLOR_RANGE properties for planes")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221014024810.21675-1-yuancan@huawei.com

drivers/gpu/drm/omapdrm/dss/dispc.c

@@ -855,11 +855,6 @@ struct csc_coef_yuv2rgb {
 	bool full_range;
 };
 
-struct csc_coef_rgb2yuv {
-	int yr, yg, yb, cbr, cbg, cbb, crr, crg, crb;
-	bool full_range;
-};
-
 static void dispc_ovl_write_color_conv_coef(struct dispc_device *dispc,
 					    enum omap_plane_id plane,
 					    const struct csc_coef_yuv2rgb *ct)