nvme: Give up when we've failed

Normally, we poll the device every so often to see if commands have
timed out. However, we'll go into the recovery state as part of failing
the drive. To account for all possibilties, if we're failed when we get
into the polling function, just stop polling: Party is over.

Sponsored by: Netflix

(cherry picked from commit d95431624f934fe4740211738fc787808005b14e)