i40e: Memory leak in i40e_config_iwarp_qvlist

Added freeing the old allocation of vf->qvlist_info in function
i40e_config_iwarp_qvlist before overwriting it with
the new allocation.

Signed-off-by: Martyna Szapar <martyna.szapar@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>