arm64: defconfig: Enable DRM_IMX8MP_DW_HDMI_BRIDGE as module

The i.MX8M Plus has support for an HDMI transmitter.  The
video is genereated by lcdif3, routed to the hdmi parallel
video interface, then fed to a DW HDMI bridge to support
up to 4K video output.
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Tested-by: Tommaso Merciai <tomm.merciai@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/configs/defconfig

@@ -890,6 +890,7 @@ CONFIG_DRM_ANALOGIX_ANX7625=m
 CONFIG_DRM_I2C_ADV7511=m
 CONFIG_DRM_I2C_ADV7511_AUDIO=y
 CONFIG_DRM_CDNS_MHDP8546=m
+CONFIG_DRM_IMX8MP_DW_HDMI_BRIDGE=m
 CONFIG_DRM_DW_HDMI_AHB_AUDIO=m
 CONFIG_DRM_DW_HDMI_CEC=m
 CONFIG_DRM_IMX_DCSS=m