drm/mediatek: Add OVL compatible name for MT8195

Add OVL compatible name for MT8195.
Without this commit, DRM won't work after modifying the device tree.

Reviewed-by: CK Hu <[e-mail]>
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Signed-off-by: Hsiao Chien Sung <[e-mail]>
Link: https://patchwork.kernel.org/project/dri-devel/patch/[e-mail]/
Signed-off-by: Chun-Kuang Hu <[e-mail]>

drivers/gpu/drm/mediatek/mtk_drm_drv.c

···
 	  .data = (void *)MTK_DISP_OVL },
 	{ .compatible = "mediatek,mt8192-disp-ovl",
 	  .data = (void *)MTK_DISP_OVL },
+	{ .compatible = "mediatek,mt8195-disp-ovl",
+	  .data = (void *)MTK_DISP_OVL },
 	{ .compatible = "mediatek,mt8183-disp-ovl-2l",
 	  .data = (void *)MTK_DISP_OVL_2L },
 	{ .compatible = "mediatek,mt8192-disp-ovl-2l",