ACPI / thermal: fix thermal driver compile error when CONFIG_PM_SLEEP is undefined

The ACPI thermal driver defines acpi_thermal_resume() when
CONFIG_PM_SLEEP is defined. This results in the following compile
error when CONFIG_PM_SLEEP is undefined.

  CC      drivers/acpi/thermal.o
drivers/acpi/thermal.c:107:8: error: ‘acpi_thermal_resume’ undeclared here (not in a function)
make[2]: *** [drivers/acpi/thermal.o] Error 1
Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/thermal.c

@@ -102,6 +102,8 @@ MODULE_DEVICE_TABLE(acpi, thermal_device_ids);
 
 #ifdef CONFIG_PM_SLEEP
 static int acpi_thermal_resume(struct device *dev);
+#else
+#define acpi_thermal_resume NULL
 #endif
 static SIMPLE_DEV_PM_OPS(acpi_thermal_pm, NULL, acpi_thermal_resume);