cpufreq: sti: add missing MODULE_DEVICE_TABLE entry for stih418

'st,stih418' is missing in the compatible list.
Add it in order to use the driver with stih418 platform.
Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/sti-cpufreq.c

@@ -293,6 +293,7 @@ module_init(sti_cpufreq_init);
 static const struct of_device_id __maybe_unused sti_cpufreq_of_match[] = {
 	{ .compatible = "st,stih407" },
 	{ .compatible = "st,stih410" },
+	{ .compatible = "st,stih418" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, sti_cpufreq_of_match);