arm64: rockchip: dts: rk3399: Use rk3399-u-boot.dtsi

Now we have
- board specific -u-boot.dtsi files for board specific u-boot
  dts changes.
- soc specific rk3399-u-boot.dtsi for soc specific u-boot
  dts changes.

So, include the rk3399-u-boot-dtsi on respective board -u-boot.dtsi
and drop the properties which are globally available in rk3399-u-boot.dtsi

Right now rk3399-u-boot.dtsi has sdmmc, spi1 u-boot,dm-pre-reloc
property and more properties and nodes can be move further based
on the requirements.

This would fix, the -u-boot.dtsi inclusion for evb, firefly, puma
boards that was accidentally merged on below commit.
"rockchip: dts: rk3399: Create initial rk3399-u-boot.dtsi"
(sha1: e05b4a4f)

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>