[rdk-b][mt7986][wifi-hal][Refactor setGuardInterval]

[Description]
Refactor setGuardInterval. Use hostapd to config short GI instead use iw set fixed GI.
Hostapd doesn't support HE mode 1600, 3200 ns GI, so we don't consider those situations.

[Release-log]
N/A

Change-Id: Ie3ffc9cb88e7391e7958778300fede7462298604
1 file changed
tree: 96cca31a94fdab7ea1f82ac94ac9102ecd2edb45
  1. src/