qcacld-3.0: Add support to get roam scan channels from fw

Firmware advertises WMI_SERVICE_ROAM_SCAN_CHANNEL_LIST_TO_HOST_SUPPORT
at the time of initialization. When user requests for roam scan channels
to driver using GETROAMSCANCHANNELS command, driver queries firmware for
roam scan channel list by sending wmi command with command id
WMI_ROAM_GET_SCAN_CHANNEL_LIST_CMDID and vdev id.
Firmware response to WMI_ROAM_GET_SCAN_CHANNEL_LIST_CMDID commmad is
WMI_ROAM_SCAN_CHANNEL_LIST_EVENTID. This event has roam scan channel
list, vdev id, connected BSSID, command_response.

Firmware issues WMI_ROAM_SCAN_CHANNEL_LIST_EVENTID event for two reasons,
one for GETROAMSCANCHANNELS command where firmware sets command_response=1
in wmi event and asynchronous event upon disconnection where firmware sets
command_response=0 in wmi event.

Change-Id: I690aca6c3f1e3aa7ae1fe54aadc839ea19446079
CRs-Fixed: 2621535
21 files changed