iavf: Combine init and watchdog state machines

Use single state machine for driver initialization and for service
initialized driver. The init state machine implemented in init_task()
is merged into the watchdog_task(). The init_task() function is
removed.

Signed-off-by: Jakub Pawlak <jakub.pawlak@intel.com>
Signed-off-by: Jan Sokolowski <jan.sokolowski@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>