meta-romulus: sort ipmi sensor config

Sort the sensor yaml config using PyYAML by loading and saving the yaml.
This is a preparation for further changes of sensor configs.

Tested: Verify the generated sensor-gen.cpp is technically the same as
        before.

Change-Id: I1315072b36236bb2eff01eb5d1507641e7978b42
Signed-off-by: Lei YU <mine260309@gmail.com>