iwlegacy: clean up suspend/resume

There's no need to export the il_pci_suspend
and il_pci_resume functions since they're only
referenced from il_pm_ops. The latter can also
be defined using SIMPLE_DEV_PM_OPS instead of
open-coding it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>