regulator: rtq2208: Add fixed LDO VOUT property and check that matches the constraints

A fixed LDO VOUT property has been added to specify the fixed_uV of the regulator_desc.
Additionally, a check has been included in this version
to ensure that the fixed_uV matches the constraints.

Signed-off-by: Alina Yu <alina_yu@richtek.com>
Link: https://msgid.link/r/39357ff9e6e5f3dec5a6f7f833a3591c0defc63a.1716870419.git.alina_yu@richtek.com


Signed-off-by: Mark Brown <broonie@kernel.org>