thermal: sti: Ignore suspend/resume functions when !PM_SLEEP

Prevents build warning:

st_thermal.c:278:12:
    warning: ‘st_thermal_suspend’ defined but not used [-Wunused-function]
st_thermal.c:286:12:
    warning: ‘st_thermal_resume’ defined but not used [-Wunused-function]
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

drivers/thermal/st/st_thermal.c

@@ -275,6 +275,7 @@ int st_thermal_unregister(struct platform_device *pdev)
 }
 EXPORT_SYMBOL_GPL(st_thermal_unregister);
 
+#ifdef CONFIG_PM_SLEEP
 static int st_thermal_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
@@ -305,6 +306,8 @@ static int st_thermal_resume(struct device *dev)
 
 	return 0;
 }
+#endif
+
 SIMPLE_DEV_PM_OPS(st_thermal_pm_ops, st_thermal_suspend, st_thermal_resume);
 EXPORT_SYMBOL_GPL(st_thermal_pm_ops);