arm64: dts: ls208xa: use a pseudo-bus to constrain usb dma size

Wrap the usb controllers in an intermediate simple-bus and use it to
constrain the dma address size of these usb controllers to the 40b
that they generate toward the interconnect. This is required because
the SoC uses 48b address sizes and this mismatch would lead to smmu
context faults [1] because the usb generates 40b addresses while the
smmu page tables are populated with 48b wide addresses.

[1]
xhci-hcd xhci-hcd.0.auto: xHCI Host Controller
xhci-hcd xhci-hcd.0.auto: new USB bus registered, assigned bus number 1
xhci-hcd xhci-hcd.0.auto: hcc params 0x0220f66d hci version 0x100 quirks 0x0000000002000010
xhci-hcd xhci-hcd.0.auto: irq 108, io mem 0x03100000
xhci-hcd xhci-hcd.0.auto: xHCI Host Controller
xhci-hcd xhci-hcd.0.auto: new USB bus registered, assigned bus number 2
xhci-hcd xhci-hcd.0.auto: Host supports USB 3.0 SuperSpeed
arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xffffffb000, fsynr=0x0, cbfrsynra=0xc01, cb=3

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>