qcacld-3.0: Make get_nss command compatible with hastings
Currently the command to get nss checks the max capability
of enable 2x2, and if the capability is 1, and the
hw mode is currently DBS, it lowers the nss capability
to 1 which is expected in helium, but not in hastings.
Fix is to check whether the device supports DBS 2x2
capability and then only downgrade the value of nss.
Change-Id: I18acef455c0790862ba786f87af776b65646aca6
CRs-Fixed: 2557587