At least on VLV but probably on other platforms too we depend on RC6
being enabled for RPM, so disable RPM until the delayed RC6 enabling
completes.

v2:
- explain the reason for the _noresume version of RPM get (Daniel)
- use the simpler 'if (schedule_work()) rpm_get();' instead of
  'if (!cancel_work_sync()) rpm_get(); schedule_work();'
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>