Currently during system s/r we enable/disable DC6, so before we do so
make sure that the firmware loading is complete.

Note that whether we need to enable DC6 for S3/S4 is still open.  At
least the firmware program is lost during S3 and we need to reprogram it
after resuming. Until this is clarified we keep the current behavior and
enable/disable DC6.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NAnimesh Manna <animesh.manna@intel.com>
Tested-by: Daniel Stone <daniels@collabora.com> # SKL
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446069547-24760-13-git-send-email-imre.deak@intel.com