POWER_TOTAL, POWER_L1, POWER_L2, POWER_L3 are int32 not uint32 #331

When the connected EV is not consuming any power I noticed a lot of values around 4.29e9 (so looking like 2s-complements).

To make sure it in fact is int32 not uint32 I used a regenerative load to feed in a a small amount of power (around -10W) through the go-e Charger Pro.
And the scaled values for POWER_L1 was constantly -10: