dts: x86: Add i226 device-tree config for Intel Alderlake

Foxville LM (0x125B) i226 variant and Intel Alder Lake platform was
used for developing and stabilizing the i226 Ethernet device driver.
However, users can reuse the provided device tree models as a reference
when enabling the support for other i226 variants and platforms.

This device-tree model include essential configurations for the i226
Ethernet controller, such as PCIe settings, interrupt mappings, Phy
MDIO, and DMA descriptor configurations.

Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>