arm64: dts: rockchip: fix PCIe domain number for rk3399

It's suggested to fix the domain number for all PCIe
host bridges or not set it at all. However, if we don't
fix it, the domain number will keep increasing ever when
doing unbind/bind test, which makes the bus tree of lspci
introduce pointless domain hierarchy. More investigation shows
the domain number allocater of PCI doesn't consider the conflict
of domain number if we have more than one PCIe port belonging to
different domains. So once unbinding/binding one of them and keep
others would going to overflow the domain number so that finally
it will share the same domain as others, but actually it shouldn't.
We should fix the domain number for PCIe or invent new indexing
ID mechanisms. However it isn't worth inventing new indexing ID
mechanisms personlly, Just look at how other Root Complex drivers
did, for instance, broadcom and qualcomm, it seems fixing the domain
number was more popular. So this patch gonna fix the domain number
of PCIe for rk3399.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>