drm/mediatek: mtk_drm_crtc: Add checks for devm_kcalloc

As the devm_kcalloc may return NULL, the return value needs to be checked
to avoid NULL poineter dereference.

Fixes: 31c5558 ("drm/mediatek: Refactor plane init")
Signed-off-by: ruanjinjie <ruanjinjie@huawei.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20221205095115.2905090-1-ruanjinjie@huawei.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

Author: ruanjinjie-eng

drivers/gpu/drm/mediatek/mtk_drm_crtc.c

@@ -945,6 +945,8 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
 
 	mtk_crtc->planes = devm_kcalloc(dev, num_comp_planes,
 					sizeof(struct drm_plane), GFP_KERNEL);
+	if (!mtk_crtc->planes)
+		return -ENOMEM;
 
 	for (i = 0; i < mtk_crtc->ddp_comp_nr; i++) {
 		ret = mtk_drm_crtc_init_comp_planes(drm_dev, mtk_crtc, i,