regulator: act8945a-regulator: make symbol act8945a_pm static

Fixes the following sparse warning:

drivers/regulator/act8945a-regulator.c:340:1: warning:
 symbol 'act8945a_pm' was not declared. Should it be static?

Fixes: 7482d6ec ("regulator: act8945a-regulator: Implement PM functionalities")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/act8945a-regulator.c

@@ -337,7 +337,7 @@ static int __maybe_unused act8945a_suspend(struct device *pdev)
 	return regmap_write(act8945a->regmap, ACT8945A_SYS_CTRL, 0x42);
 }
 
-SIMPLE_DEV_PM_OPS(act8945a_pm, act8945a_suspend, NULL);
+static SIMPLE_DEV_PM_OPS(act8945a_pm, act8945a_suspend, NULL);
 
 static void act8945a_pmic_shutdown(struct platform_device *pdev)
 {