Import dhcpcd-6.1.0 with the following changes:
* Fixed a segfault when configuring a static route in dhcpcd.conf
* Merged IPv6 ND and RA codebases
* Persistent configuration is now a default option in dhcpcd.conf
* Store configured IPv4 addresses against the interface so we only add
  them if actually missing to avoid RTM_DELADDR/NEWADDR loops on some OS's
* waitip now supports waiting for any, IPv4, IPv6 or both protocols
* DHCPv6 addresses are added with a /128 prefix and should not attempt to
  associate with any existing prefix or make one up as per RFC 5942
* Fix initial carrier status
* Fix requesting >1 DHCPv6 address

Fixes PR bin/48140