drm/amd/display: fix a compile warning

Fix comile warning like,
  CC [M]  drivers/gpu/drm/i915/gvt/execlist.o
  CC [M]  drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv50.o
  CC [M]  drivers/gpu/drm/radeon/btc_dpm.o
  CC [M]  drivers/isdn/hisax/avm_a1p.o
  CC [M]  drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_dpp.o
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_hw_sequencer.c: In function ‘dcn10_update_mpcc’:
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_hw_sequencer.c:1903:9: warning: missing braces around initializer [-Wmissing-braces]
  struct mpcc_blnd_cfg blnd_cfg = {0};
         ^
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_hw_sequencer.c:1903:9: warning: (near initialization for ‘blnd_cfg.black_color’) [-Wmissing-braces]
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c

@@ -1917,7 +1917,7 @@ static void update_dpp(struct dpp *dpp, struct dc_plane_state *plane_state)
 static void dcn10_update_mpcc(struct dc *dc, struct pipe_ctx *pipe_ctx)
 {
 	struct hubp *hubp = pipe_ctx->plane_res.hubp;
-	struct mpcc_blnd_cfg blnd_cfg = {0};
+	struct mpcc_blnd_cfg blnd_cfg = {{0}};
 	bool per_pixel_alpha = pipe_ctx->plane_state->per_pixel_alpha && pipe_ctx->bottom_pipe;
 	int mpcc_id;
 	struct mpcc *new_mpcc;