net: xilinx: axi_emac: Cleanup of of_to_plat()

net: xilinx: axi_emac: Cleanup of of_to_plat()

There are lot of accesses to priv data in of_to_plat(), which is incorrect.
Create a platform data structure and use it in of_to_plat(), then copy all
platform data to priv data in probe.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>