net: phy: xilinx_phy: Get rid of using property xlnx, phy-type

As the xlnx,phy-type device tree property is deprecated and phy-mode
is being used, so removing the code references of xlnx,phy-type.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Link: https://lore.kernel.org/r/20231010030436.11854-1-venkatesh.abbarapu@amd.com


Signed-off-by: Michal Simek <michal.simek@amd.com>