Map the packet QoS value to a TID before looking it up in the
per node + TID AMPDU state array.

The TX A-MPDU state used to be per-AC, but I changed it to be
per-TID because it /is/ negotiated per-TID. However this is
not aligned correctly and A-MPDU on eg the voice queue would
cause a mismatch and thus packets to get dropped.

(TIDs 8..15 are special and session based, not traffic QoS based.)

I noticed this because "ssh host" failed after a while, but
"telnet host 22" succeeded. It turned out that frames weren't
making it to the driver transmit path and I traced it
back to being dropped here. Traffic worked for a while until
A-MPDU TX was negotiated, and then all traffic on a TID
would fail until the 802.11 association was re-established.

Locally tested:

• iwn 6205, STA mode - forced traffic into VO AC/TID

MFC after: 1 week