pwm: pwm-tiecap: add CONFIG_PM_SLEEP to suspend/resume functions

This patch adds CONFIG_PM_SLEEP to suspend/resume functions to fix
the following build warning when CONFIG_PM_SLEEP is not selected.

drivers/pwm/pwm-tiecap.c:314:12: warning: 'ecap_pwm_suspend' defined but not used [-Wunused-function]
drivers/pwm/pwm-tiecap.c:328:12: warning: 'ecap_pwm_resume' defined but not used [-Wunused-function]
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

drivers/pwm/pwm-tiecap.c

@@ -311,6 +311,7 @@ void ecap_pwm_restore_context(struct ecap_pwm_chip *pc)
 	writew(pc->ctx.ecctl2, pc->mmio_base + ECCTL2);
 }
 
+#ifdef CONFIG_PM_SLEEP
 static int ecap_pwm_suspend(struct device *dev)
 {
 	struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
@@ -337,6 +338,7 @@ static int ecap_pwm_resume(struct device *dev)
 	ecap_pwm_restore_context(pc);
 	return 0;
 }
+#endif
 
 static SIMPLE_DEV_PM_OPS(ecap_pwm_pm_ops, ecap_pwm_suspend, ecap_pwm_resume);