qcacld-3.0: Add check for DBS mode in start bss

Currently the driver doesn't handle the nss update
if a prior connection is already present in DBS
mode. Suppose if a STA is already connected in
5ghz and the SAP comes up in 2.4ghz, the beacon
template should be updated with NSS = 1

Fix is to check whether the current hw_mode is in
DBS or not, and change the nss in the beacon template
accordingly

Change-Id: I54ead1fd26d705a821160b5bc5d816df1d2ab8f4
CRs-Fixed: 2288307
1 file changed