working. We store v4 and v6 addresses as a union but for v4-mapped
addresses only store the 32bits w/o the ::ffff: word. That failed the
check as for example 127.0.0.1 would be ::7f00:1 rather than ::ffff:7f00:1
and the IN6_IS_ADDR_V4MAPPED() never worked here. Given we can hardly get
here with an unbound local address or invalid inp_vflags remove the check.
Reported by: tuexen
Reviewed by: tuexen
MFC after: 3 days