greybus: interface: clear upper 16-bits of version_id and product_id

Current userspace looks through the sysfs interface entries for
matching vendor_id and product_id any time an interface is opened
by module developers.  The upper 16-bits of ES3 vendor_id and
product_id contain a reverse mask of the lower 16-bits.  This
additional information is never used and should be removed so
that every consumer of these sysfs entries doesn't have to perform
the same bit clearing logic.

Signed-off-by: Michael Scott <michael.scott@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>