FdtBusDxe: Finish DtIoParseProp (EFI_DT_VALUE_U128)

[andreiw]

Support EFI_DT_VALUE_DEVICE and EFI_DT_VALUE_U128.

[andreiw]

EFI_DT_VALUE_DEVICE can be implemented similar to fdt_get_path, but checking against phandle instead of nodeoffset. Also, instead of building an ASCII string, we can directly build a device path. Using existing device path lib is awkward, especially since we need to track back.... instead let's create a list of wrapped DP nodes, which keeps created nodes in a linked list and has an operation to flatten. Actually, more like a stack, where newly added DP nodes are added at the font.

[andreiw]

EFI_DT_VALUE_DEVICE is now supported (as of Sep 2024) - not efficiently, but it works. Optimizations welcome...