net: xilinx_axi: Use interface type instead of zero

Pass appropriate interface type to phy_connect
instead of zero.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>