media/bcm2835-unicam: Add support for configuration via MC API

media/bcm2835-unicam: Add support for configuration via MC API

Adds Media Controller API support for more complex pipelines.
libcamera is about to switch to using this mechanism for configuring
sensors.

This can be enabled by either a module parameter, or device tree.

Various functions have been moved to group video-centric and
mc-centric functions together.

Based on a similar conversion done to ti-vpe.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
media: bcm2835-unicam: Fixup for 5.18 and new get_mbus_config struct

The number of active CSI2 data lanes has moved within the struct
v4l2_mbus_config used by the get_mbus_config API call.
Update the driver to match the changes in mainline.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>