Add a sandbox LDO3 with a configurable 1.8V to 3.3V range and use it to test regulator_set_value_clamp(). Test in-range requests, clamping against the regulator limits, invalid ranges outside the regulator limits and a min value higher than max. Signed-off-by: Jonas Karlman <jonas@kwiboo.se> Reviewed-by: Peng Fan <peng.fan@nxp.com> Signed-off-by: Peng Fan <peng.fan@nxp.com>