hostapd: Config knobs framework to support MPDU spacing and Tx-STBC.

This CL allows configknobs to configure MPDU start spacing
and Tx-STBC in HT and VHT capabilities.

These parameters takes effect on sending association
response by AP.

Mini MPDU start spacing: Determines the minimum time between
the start of adjacent MPDUs within an A-MPDU that the
STA can receive.

BUG=b:69065819
TEST=Tested all the values supported by min mpdu start spacing
and same verified with sniffer capture in assocciation response
frame. Ran throughput test for all 0-7 values in shild room.
For VHT Tx-STBC verified in assoc response frame sent by AP.

Change-Id: I39ea5290fc39a6f2787f44866f83b2f64a18e0f7
Reviewed-on: https://chromium-review.googlesource.com/881061
Commit-Ready: sharanbasappa.sali sharanbasappa.sali <sharanbasappa.sali@globaledgesoftware.corp-partner.google.com>
Tested-by: sharanbasappa.sali sharanbasappa.sali <sharanbasappa.sali@globaledgesoftware.corp-partner.google.com>
Reviewed-by: Srinivasa duvvuri <sduvvuri@google.com>
3 files changed