nm-platform: add the `a_no_auto_noprefixroute` flag
In the situation of deactivating the connection on the loopback interface, the IP addresses 127.0.0.1/8 and ::1/128 have to be preserved, but the noprefixroute flag should not be added also.
In order to extend such a capability for
nm_platform_ip_address_sync()
later, add the
a_no_auto_noprefixroute
flag to the __NMPlatformIPAddress_COMMON
in
the first place.