thermal: add missing Kconfig dependency

Otherwise THERMAL_HWMON can be selected when HWMON=n and THERMAL=n, which
fails to build.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/thermal/Kconfig

@@ -15,6 +15,7 @@ menuconfig THERMAL
 
 config THERMAL_HWMON
 	bool "Hardware monitoring support"
+	depends on THERMAL
 	depends on HWMON=y || HWMON=THERMAL
 	help
 	  The generic thermal sysfs driver's hardware monitoring support