LinuxKPI: 802.11: increase mbufq lengths

Increase the mbufq lengths we use in the RX and TX path to decouple
the lower and upper parts (currently using taskqs which likely need
to be replaced as well now -- was asked not to add more sophisticated
concepts 2-ish years ago).
The old values of IFQ_MAXLEN (50) are a tad too small so bump them
to 32 * NAPI_POLL_WEIGHT (32 * 64) which seems to be mostly enough
now not to drop mbufs anymore (by not overflowing the queues).
As a side effect TCP became a lot happier as well growing throughput
towards where UDP is already. There is more fish to fry but we
are also doing ~750 Mbits/sec TX and 400 Mbit/s RX TCP at VHT160 now.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days