arm64: dts: rockchip: rename rk3588-rock-5b.dtsi

As subsequent patches will add ROCK 5T support, rename the .dtsi file to
reflect that it's shared between ROCK 5B, ROCK 5B+ and ROCK 5T.

This is done separately from moving the 5B and 5B+ only nodes to a
common tree so that the history stays bisectable and the diff easily
reviewable.

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://lore.kernel.org/r/20250520-add-rock5t-v2-2-1f1971850a20@collabora.com


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