iavf: Fix __IAVF_RESETTING state usage

The setup of __IAVF_RESETTING state in watchdog task had no
effect and could lead to slow resets in the driver as
the task for __IAVF_RESETTING state only requeues watchdog.
Till now the __IAVF_RESETTING was interpreted by reset task
as running state which could lead to errors with allocating
and resources disposal.

Make watchdog_task queue the reset task when it's necessary.
Do not update the state to __IAVF_RESETTING so the reset task
knows exactly what is the current state of the adapter.

Fixes: 898ef1cb

 ("iavf: Combine init and watchdog state machines")
Signed-off-by: Slawomir Laba <slawomirx.laba@intel.com>
Signed-off-by: Phani Burra <phani.r.burra@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>