eeepc-laptop: switch to dev_pm_ops

This also involves switching the resume handler from the acpi device
to the platform device.  Using the more fine grained handlers allows
two improvements:

1. We only need to recheck rfkill state after resume from hibernation.

2. The wireless LED workaround accounts for up to 1.1s out of 1.7s
resuming devices (when wireless is enabled).  We can limit the
workaround to thaw(), so that it only delays suspend to disk.

The workaround is only likely to help when hibernation is aborted.
Suspend to ram cannot be aborted by the user.  Device suspend errors may
well happen before eeepc-laptop would even be frozen.  Suspend errors
which happen after that could be pretty funky anyway.

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Len Brown <len.brown@intel.com>