MFV r333668:

Vendor import two upstream commits:
c1bb8784abd3ca978e376b0d10e324db0491237b
9c4af7213cc2543a1f5586d8f2c19f86aa0cbe72

When using tcpdump -I -i wlanN and wlanN is not a monitor mode VAP,
tcpdump will print an error message saying rfmon is not supported.

Give a concise explanation as to how one might solve this problem by
creating a monitor mode VAP.

MFC after: 1 month
Approved by: hselasky (mentor), kib (mentor)
Sponsored by: Mellanox Technologies