net: ipvlan_l3s: fix kconfig dependency warning

Fix the kconfig warning in IPVLAN_L3S when neither INET nor IPV6
is enabled:

WARNING: unmet direct dependencies detected for NET_L3_MASTER_DEV
  Depends on [n]: NET [=y] && (INET [=n] || IPV6 [=n])
  Selected by [y]:
  - IPVLAN_L3S [=y] && NETDEVICES [=y] && NET_CORE [=y] && NETFILTER [=y]

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Mahesh Bandewar <maheshb@google.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>