dts: edtlib: Add 'type: path' for path references

Add binding support for a 'path' property type, for properties that are
assigned node paths. Usually, paths are assigned with path references
like 'foo = &label' (common in /chosen), but plain strings are accepted
as well as long as they're valid paths.

The 'path' type is mostly for completeness at this point, but might be
useful for https://github.com/zephyrproject-rtos/zephyr/issues/21623.
The support is there already in dtlib.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
5 files changed