[media] ths8200: Include linux/of.h header

'of_match_ptr' is defined in linux/of.h. Include it explicitly to
avoid build breakage in the future.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/i2c/ths8200.c

@@ -19,6 +19,7 @@
 
 #include <linux/i2c.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/v4l2-dv-timings.h>
 
 #include <media/v4l2-dv-timings.h>