ARM: dts: rockchip: rk3588: Move bootph-all props to common file

Move bootph-all prop to common SoC dt file, because they are typically used
by multiple boards.
Unreferenced nodes are removed from the SPL device tree during a
normal build.

Suggested-by: Jonas Karlman <jonas@kwiboo.se>
Signed-off-by: Eugen Hristev <eugen.hristev@collabora.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>