net: macb: Add compatible string for Zynq Ultrascale+ MPSoC

Add compatible string and config structure for Zynq Ultrascale+ MPSoC

Signed-off-by: Harini Katakam <harinik@xilinx.com>
Reviewed-by: Punnaiah Choudary Kalluri <punnaia@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>