iwlwifi: mvm: support unification of INIT and RT images

For a000 devices the INIT and RT images are unified to one
image.
The changes in the flow are the following:
* Driver load only RT firmware - meaning that the nvm access
  command will be done in the RT image load flow.
* A new command (NVM_ACCESS_COMPLETE) now signals to the FW that
  the driver is done accessing the NVM and FW can proceed with phy
  calibrations.
* Phy DB is no longer sent from INIT FW to be restored by driver
  for the RT FW - all the phy DB is now internal to the FW.
  INIT complete will now follow the NVM access command, without
  phy DB calls before.
* Paging command is sent earlier in the flow before NVM access
  to enable a complete load of FW.
* caution must be care when restart is called since we may have
  not completed init flow even though we are in RT firmware.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>