arm64: dts: rockchip: Add sfc node to rk3588s

Add SFC (SPI Flash) to RK3588S SOC.

Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Muhammed Efe Cetin <efectn@6tel.net>
Link: https://lore.kernel.org/r/d36a64edfaede92ce2e158b0d9dc4f5998e019e3.1696878787.git.efectn@6tel.net


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