qcacld-3.0: Set 2g vht20 cfg by both target capability and ini config

2g vht20 config should be decided by both capability indicated
by target and ini config. Only when F/W indicates 2g vht20
supported and ini config gEnableVhtFor24GHzBand=1, 2g vht20 is
enabled.

Change-Id: I5b7ad8f82b6000096327c501dc84ad05480ef0fd
CRs-Fixed: 2381514
4 files changed