ACPI / battery: remove duplicated include from battery.c

Remove duplicated include.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/battery.c

@@ -35,7 +35,6 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>
-#include <linux/delay.h>
 #include <asm/unaligned.h>
 
 #ifdef CONFIG_ACPI_PROCFS_POWER