arm64: dts: rockchip: add clock to vo1-grf syscon on rk3588

The VO*-general-register-files need a clock, so add the correct one.

Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20240227210521.724754-1-heiko@sntech.de