net: conn: fix supplicant l2 recv unexpected frame

Supplicant create AF_PACKET proto ETH_P_PAE socket but receive other
frames like ICMP, UDP and causes following issues.
1. When frame len exceeds MTU, net_pkt_clone cannot clone pkt.
   Thus dropped it and print warning log.
2. It will lower throughput performance as every packet is cloned.

Fix it by conn_raw_socket does not deliver pkts protocol not macted,
after l2 processed, unless conn is all packets.

Signed-off-by: Fengming Ye <frank.ye@nxp.com>