[rdk-b][mt7986][wifi-hal][Add GuardInterval functions]

[Description]
Add GuardInterval functions. And record GI value in the file.
The function getRadioGuardInterval and setRadioGuardInterval is deprecated, So I implement them just call the corresponding new functions.
Use iw instead of hostapd beacause hostapd can not set GI in he mode.

[Release-log]
N/A

Change-Id: I7cb89b583c6d53650f641bc80fbc45100916a92a
1 file changed
tree: dc909c0d58939067f0e9142ff91addad91def50a
  1. src/