iavf: missing unlocks in iavf_watchdog_task()

This code was re-organized and there some unlocks missing now.

Fixes: 898ef1cb ("iavf: Combine init and watchdog state machines")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>