iavf: do not override the adapter state in the watchdog task (again)

The watchdog task incorrectly changes the state to __IAVF_RESETTING,
instead of letting the reset task take care of that. This was already
resolved by commit 22c8fd71 ("iavf: do not override the adapter
state in the watchdog task") but the problem was reintroduced by the
recent code refactoring in commit 45eebd62 ("iavf: Refactor iavf
state machine tracking").

Fixes: 45eebd62

 ("iavf: Refactor iavf state machine tracking")
Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>