ARM: UniPhier: add xHCI device nodes to PH1-Pro4 device tree

Each USB port corresponds to the following IP core:
 port0: xHCI (0x65a00000) SS+HS
 port1: xHCI (0x65c00000) HS (SS PHY is not implemented)
 port2: EHCI (0x5a800100) HS
 port3: EHCI (0x5a810100) HS

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>