arm64: dts: rockchip: Update VPLL Frequency for RGB30

Set the VPLL frequency for the RGB30 to 292.5MHz to support running
the 720x720 display panel at 59.97hz. Without this change, the panel
runs at 59.08hz.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Link: https://lore.kernel.org/r/20231018153357.343142-3-macroalpha82@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>