staging: most: dim2: update renesas compatible string

Use "renesas,rcar-gen3-mlp" instead of "rcar,medialb-dim2"
- the documented vendor prefix for Renesas is "renesas,"
- existing r-car devices use "rcar-genN-XXX" pattern.

There are currently no in-tree users to update.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Link: https://lore.kernel.org/r/20211226082530.2245198-2-nikita.yoush@cogentembedded.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>