qcacmn: Get the firmware capability NAN_VDEV_SUPPORT
Firmware advertises service capability bit NAN_VDEV_SUPPORT for
separate NAN vdev creation. This capability can be used to create
separate interface for NAN discovery and process corresponding
commands from userspace.
Change-Id: I4f81b354433c34e8bfe264f69e4eeaf6670f2fac
CRs-Fixed: 2592016