s3c-adc-battery: Fix compilation error due to missing header (module.h)

Add linux/module.h to fix this compilation error:

drivers/power/s3c_adc_battery.c:435:15: error: expected declaration specifiers or ‘...’ before string constant
drivers/power/s3c_adc_battery.c:435:1: warning: data definition has no type or storage class
drivers/power/s3c_adc_battery.c:435:1: warning: type defaults to ‘int’ in declaration of ‘MODULE_AUTHOR’
drivers/power/s3c_adc_battery.c:435:15: warning: function declaration isn’t a prototype
drivers/power/s3c_adc_battery.c:436:20: error: expected declaration specifiers or ‘...’ before string constant
drivers/power/s3c_adc_battery.c:436:1: warning: data definition has no type or storage class
drivers/power/s3c_adc_battery.c:436:1: warning: type defaults to ‘int’ in declaration of ‘MODULE_DESCRIPTION’
drivers/power/s3c_adc_battery.c:436:20: warning: function declaration isn’t a prototype
drivers/power/s3c_adc_battery.c:437:16: error: expected declaration specifiers or ‘...’ before string constant
drivers/power/s3c_adc_battery.c:437:1: warning: data definition has no type or storage class
drivers/power/s3c_adc_battery.c:437:1: warning: type defaults to ‘int’ in declaration of ‘MODULE_LICENSE’
drivers/power/s3c_adc_battery.c:437:16: warning: function declaration isn’t a prototype
make[2]: *** [drivers/power/s3c_adc_battery.o] Error 1

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Ian Lartey <ian@opensource.wolfsonmicro.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>