ieee802154: hwsim: avoid possible crash in hwsim_del_edge_nl()

Both MAC802154_HWSIM_ATTR_RADIO_ID and MAC802154_HWSIM_ATTR_RADIO_EDGE
must be present to avoid a crash.

Fixes: f25da51f ("ieee802154: hwsim: add replacement for fakelb")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20210621180244.882076-1-eric.dumazet@gmail.com


Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>