soc: qcom: spmi-pmic: convert hex numbers to lowercase

There are some IDs that are written in uppercase. For consistency
convert them to lowercase.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Caleb Connolly <caleb.connolly@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220922082925.17975-1-luca.weiss@fairphone.com