sbs-battery: add min design voltage to sbs-battery

sbs-battery has a max design voltage but not a min design voltage field.
The SBS spec only has one design voltage:
http://www.sbs-forum.org/specs/sbdat110.pdf

Currently this is being used for max design voltage. This patch uses it
for min design voltage as well.

Signed-off-by: Simon Que <[e-mail]>
Reviewed-by: Simon Glass <[e-mail]>
Reviewed-by: Todd Broch <[e-mail]>
Signed-off-by: Javier Martinez Canillas <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/sbs-battery.c

···
 	REG_FULL_CHARGE_CAPACITY_CHARGE,
 	REG_DESIGN_CAPACITY,
 	REG_DESIGN_CAPACITY_CHARGE,
-	REG_DESIGN_VOLTAGE,
+	REG_DESIGN_VOLTAGE_MIN,
+	REG_DESIGN_VOLTAGE_MAX,
 	REG_MANUFACTURER,
 	REG_MODEL_NAME,
 };
···
 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN, 0x18, 0, 65535),
 	[REG_DESIGN_CAPACITY_CHARGE] =
 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 0x18, 0, 65535),
-	[REG_DESIGN_VOLTAGE] =
+	[REG_DESIGN_VOLTAGE_MIN] =
+		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN, 0x19, 0, 65535),
+	[REG_DESIGN_VOLTAGE_MAX] =
 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, 0x19, 0, 65535),
 	[REG_SERIAL_NUMBER] =
 		SBS_DATA(POWER_SUPPLY_PROP_SERIAL_NUMBER, 0x1C, 0, 65535),
···
 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
 	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
 	POWER_SUPPLY_PROP_SERIAL_NUMBER,
+	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
 	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
 	POWER_SUPPLY_PROP_ENERGY_NOW,
 	POWER_SUPPLY_PROP_ENERGY_FULL,
···
 		break;
 
 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
 	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
 	case POWER_SUPPLY_PROP_CURRENT_NOW:
 	case POWER_SUPPLY_PROP_CHARGE_NOW:
···
 	case POWER_SUPPLY_PROP_TEMP:
 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
 	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
 	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
 		ret = sbs_get_property_index(client, psp);
 		if (ret < 0)