power: supply: surface-battery: Make some symbols static

The sparse tool complains as follows:

drivers/power/supply/surface_battery.c:700:1: warning:
symbol 'dev_attr_alarm' was not declared. Should it be static?
drivers/power/supply/surface_battery.c:805:1: warning:
symbol 'surface_battery_pm_ops' was not declared. Should it be static?

This symbol is not used outside of surface_battery.c, so this
commit marks it static.

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Qiheng Lin <[e-mail]>
Acked-by: Maximilian Luz <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/supply/surface_battery.c

···
 	return count;
 }
 
-DEVICE_ATTR_RW(alarm);
+static DEVICE_ATTR_RW(alarm);
 
 static struct attribute *spwr_battery_attrs[] = {
 	&dev_attr_alarm.attr,
···
 {
 	return spwr_battery_recheck_full(dev_get_drvdata(dev));
 }
-SIMPLE_DEV_PM_OPS(surface_battery_pm_ops, NULL, surface_battery_resume);
+static SIMPLE_DEV_PM_OPS(surface_battery_pm_ops, NULL, surface_battery_resume);
 
 static int surface_battery_probe(struct ssam_device *sdev)
 {