Don't allow start_yr, end_yr, and align_yr to be set in user_nl_datm_streams when it's set by the xml variables DATM_YR_*

Currently you can set start_yr,end_yr and align_yr to be set both by user_nl_datm_streams and by setting the DATM_YR_* xml variables with xmlchange. Since, this can lead to a contradiction it would be good to disallow it being set by user_nl_datm_streams and the user told to modify it with xmlchange.

We do this same sort of thing in other components as well such as CTSM.