Add a new compatible for the rk3568 Rockchip SoC, which also features an
RGA, which is called RGA2 in the TRM Part2. It is the same core as used
on the rk3288, which documents the same RGA2.

Specify a new compatible for the rk3568 to be able to handle unknown
SoC-specific differences in the driver.
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Link: https://lore.kernel.org/r/20230119-rk3568-rga-v1-1-43d4d14365e6@pengutronix.deSigned-off-by: Heiko Stuebner <heiko@sntech.de>