qcacmn: Add support for WLAN thermal mitigation

As a part of a new requirement, the WLAN subsystem needs to perform
thermal mitigation action as per the thermal state of the device. The
platform driver sends the notification with the thermal state and the
host performs the required appropriate action. The actions include
blocking northbound communication as a maximum power save state and
throttling (via duty cycle control) as an intermediate power save
action. The driver switches states and maintains the configured states
across load/unload.

Make changes to perform registration with the platform driver, act as
per the thermal state as received by the platform driver and
communicate with FW regarding the mitigation action to be performed.

The communication with the FW is done via the WMI command
WMI_THERM_THROT_SET_CONF_CMDID.

Change-Id: Icbbfd4d75e191b2e9b523afc4806fc714a4a251e
CRs-Fixed: 2468792