regulator: qcom-rpmh: PM8550 ldo11 regulator is an nldo

This fixes the definition of the PM8550 ldo11 regulator matching it's
capabilities since this LDO is designed to work between 1,2V and 1,5V.

Fixes: e6e3776d ("regulator: qcom-rpmh: Add support for PM8550 regulators")
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>