Use the VERSIONCRC to determine the exact device version. According to
the datasheet this register can be used as device identifier. The
identification is needed since some tps6586x regulators use a different
voltage table.
Signed-off-by: Stefan Agner <stefan@agner.ch> Reviewed-by: Thierry Reding <treding@nvidia.com> Acked-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>