PM / devfreq: tegra30: Include appropriate header

It's not very correct to include mod_devicetable.h for the OF device
drivers and of_device.h should be included instead.
Reviewed-by: NChanwoo Choi <cw00.choi@samsung.com>
Tested-by: NPeter Geis <pgwipeout@gmail.com>
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>

drivers/devfreq/tegra30-devfreq.c

@@ -13,7 +13,7 @@
 #include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/module.h>
-#include <linux/mod_devicetable.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_opp.h>
 #include <linux/reset.h>