lantiq: kernel 4.14: update dts files

Updated the devicetree source files to make use of the following
upstreamed drivers:

 - xrx200 ethernet phy
 - reset controller unit
 - dwc2
 - fpi

Use our custom xrx200 ethernet phy compatible to support boards, which
have switched the vr9 revision during lifetime, with a single devicetree
source file.

By switching to the dwc2 driver + usb phy framework, we don't need to used
our custom gpio power patch and can use a fixed regulator instead.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Mathias Kresin <dev@kresin.me>