qcacld-3.0: Properly set htCapable and vhtCapable

In an IOT scenario, client is VHT capable and is carrying
VHT IE in assoc-req frame while our SAP is configured as
HT only.

Key points here are the phymode and vht_flag populated in
WMI_PEER_ASSOC_CMDID.

phymode is set with SAP's own capability taken into considertion
while vht_flag is not. This leads to FW TX data using VHT data
rates.

Fix is to properly set htCapable and vhtCapable with SAP's own
capability taken into considertion.

Change-Id: I7493e90aa744665569093d3a67714c1224d010a0
CRs-Fixed: 2740102