HSD #22012268110: net: ethernet: altera: E-Tile fixed link implementation

commit ac3fb1966ababce5ad9c674479b06f4bb6cb6e76 from
https://github.com/altera-opensource/linux-socfpga.git

 socfpga-5.15.100-lts.

This patch implements fixed link device tree binding handling at the E-Tile
ethernet MAC driver as the E-Tile ethernet MAC is not connected to a normal
MDIO-managed PHY device.

Signed-off-by: Tham, Mun Yew <mun.yew.tham@intel.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>