power: supply: test_power: Fix battery_current initial value

Since default battery_status is POWER_SUPPLY_STATUS_DISCHARGING,
we should change default battery_current to a negative value.
Signed-off-by: LH Lin <lh.lin@mediatek.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/test_power.c

@@ -34,7 +34,7 @@ static int battery_technology		= POWER_SUPPLY_TECHNOLOGY_LION;
 static int battery_capacity		= 50;
 static int battery_voltage		= 3300;
 static int battery_charge_counter	= -1000;
-static int battery_current		= 1600;
+static int battery_current		= -1600;
 
 static bool module_initialized;