Restoring configuration registers is only needed when we hand control
to the firmware. This is never the case with runtime power
management. The device will autosuspend whenever not used, so avoid
useless register writes by defining suspend/resume only, and not
runtime_suspend/runtime_resume.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>