ice: use repr instead of vf->repr

Extract repr from vf->repr as it is often use in the ice_repr_rem().

Remove meaningless clearing of q_vector and netdev pointers as kfree is
called on repr pointer.

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>