media: rcar-vin: Remove redundant compatible values

The mandatory compatible value 'renesas,rcar-gen2-vin' was added to all
Gen2 DTS files in 2017, remove the redundant device specific values from
the driver.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>