Make this function return a pointer to the boardinfo instead of an index.
Since it's not typical, add a comment to clarify why this legacy driver
does a probe.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>