arm64: defconfig: Enable DRM_SUN6I_DSI

Now, Allwiner MIPI-DSI support is available for ARM64
Allwinner SoC like A64. So, let's build it as a module.
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

arch/arm64/configs/defconfig

@@ -548,6 +548,7 @@ CONFIG_ROCKCHIP_DW_MIPI_DSI=y
 CONFIG_ROCKCHIP_INNO_HDMI=y
 CONFIG_DRM_RCAR_DU=m
 CONFIG_DRM_SUN4I=m
+CONFIG_DRM_SUN6I_DSI=m
 CONFIG_DRM_SUN8I_DW_HDMI=m
 CONFIG_DRM_SUN8I_MIXER=m
 CONFIG_DRM_MSM=m