if_iwm - Check sc->sc_attached flag in suspend/resume callbacks.
- There is (almost) nothing to do in suspend/resume if if_iwm has failed
during initialization (e.g. because of firmware load failure) and was
already uninitialized by iwm_detach_local().
Submitted by: Augustin Cavalier <waddlesplash@gmail.com> (Haiku)
Obtained from: DragonFlyBSD (67b5e090efb225654815fed91020db6cfc16bb19)