floppy: Switch driver to dev_pm_ops

Gets rid of the following warning:
Platform driver 'floppy' needs updating - please use dev_pm_ops

[rjw: Fixed up the definition of floppy_pm_ops.]

Signed-off-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>