ena: do not call reset if device is unresponsive

If the device becomes unresponsive, the driver will not be able to
finish the reset process correctly. Timeout during version validation
indicates that the device is currently not responding. In that case
do not perform the reset and instead reschedule timer service. Because
of that the driver will continue trying to reset the device until it
succeeds or is detached.

Submitted by: Dawid Gorecki <dgr@semihalf.com>
Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.

(cherry picked from commit d10ec3ad7739a6f621d398d034632f68f647d72f)