arm64: dts: rockchip: extent bus-ranges of PCIe for rk3399

In order to support multiple hierarchy of PCIe buses,
for instance, PCIe switch, we need to extent bus-ranges
to as max as possible. We have 32 regions and could support
up to 31 buses except bus 0 for our root bridge.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>