thermal: use defaultdict instead of special casing a nonexistent element
thermal: use defaultdict instead of special casing a nonexistent element

JaviMerino/trappy,joelagnel/trappy,ARM-software/trappy,ARM-software/trappy,ARM-software/trappy,bjackman/trappy,ARM-software/trappy,bjackman/trappy,sinkap/trappy,JaviMerino/trappy,bjackman/trappy,bjackman/trappy,sinkap/trappy,JaviMerino/trappy,derkling/trappy,derkling/trappy,joelagnel/trappy,joelagnel/trappy,sinkap/trappy,joelagnel/trappy,sinkap/trappy,derkling/trappy