Revert "net/ipv6: Bail early if user only wants cloned entries"

This reverts commit 08e814c9

: as we
are preparing to fix listing and dumping of IPv6 cached routes, we
need to allow RTM_F_CLONED as a flag to match routes against while
dumping them.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>