arm64: dts: imx8mm-beacon: Enable OV5640 Camera

The baseboard has support for a TDNext 5640 Camera which
uses an OV5640 connected to a 2-lane CSI2 interface.

With the CSI and mipi_csi2 drivers pointing to an OV5640 camera, the media
pipeline can be configured with the following:

    media-ctl --links "'ov5640 1-003c':0->'imx7-mipi-csis.0':0[1]"

The camera and various nodes in the pipeline can be configured for UYVY:
    media-ctl -v -V "'ov5640 1-003c':0 [fmt:UYVY8_1X16/640x480 field:none]"
    media-ctl -v -V "'csi':0 [fmt:UYVY8_1X16/640x480 field:none]"

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>