Energy: Fixed host parsing assertion + mem leak

Energy: Fixed host parsing assertion + mem leak

When parsing the platform file with energy,
using the old watt description syntax
"watt_min:watt_max" instead of
"watt_idle:watt_min:watt_max" led to obscure
OOB error, the error message should now be
clearer.

Also found a little memory leak,
msg_idle was not freed.