[PATCH v2 2/2] arm64: dts: rockchip: add MNT Reform 2

[Jimmy Hon]

The RCORE looks like a carrier board for the Firefly iCore RK3588Q SoM [1].
So it would be better to restructure the DTS as a dtsi for the SoM and
a board DTS which includes the SoM dtsi.

That's similar to the structure of the Firefly ITX-RK3558J board which 
uses the rk3588-firefly-core-3588j.dtsi. [2]

[1] https://source.mnt.re/reform/mnt-reform-rk3588-som
[2] https://lore.kernel.org/linux-rockchip/20241216214152.58387-1-shimrrashai@gmail.com/#t