ACPI: battery: include linux/power_supply.h

acpi/battery.h uses 'struct power_supply *', but fails to
include/create any declaration of the type. Include linux/
power_supply.h to fix that.
Signed-off-by: NBarnabás Pőcze <pobrn@protonmail.com>
[ rjw: Subject edit ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

include/acpi/battery.h

@@ -2,6 +2,8 @@
 #ifndef __ACPI_BATTERY_H
 #define __ACPI_BATTERY_H
 
+#include <linux/power_supply.h>
+
 #define ACPI_BATTERY_CLASS "battery"
 
 #define ACPI_BATTERY_NOTIFY_STATUS	0x80