Handle null pointer returned by of_overlay_fix_path properly

[Michael Riesch]

Hi all,

The function of_overlay_fix_path returns NULL in certain error cases but
of_overlay_apply_symbols (which is the only caller) does not check the
return value. For broken overlays this may result in an exception, which
is probably not the best way to deal with this situation. I am not sure
though what would be a good way to handle this error condition. Since
the call happens in a loop, we may want to ignore the symbol in question
and continue? Any thoughts?

Best regards,
Michael