e1000e: Only run S0ix flows if shutdown succeeded

If the shutdown failed, the part will be thawed and running
S0ix flows will put it into an undefined state.

Reported-by: Alexander Duyck <alexander.duyck@gmail.com>
Reviewed-by: Alexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Tested-by: Yijun Shen <Yijun.shen@dell.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>