ipv6: fib_rules: Add port mask matching

Extend IPv6 FIB rules to match on source and destination ports using a
mask. Note that the mask is only set when not matching on a range.

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250217134109.311176-5-idosch@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>