iio: humidity: dht11: Switch from of headers to mod_devicetable.h

There is nothing directly using of specific interfaces in this driver,
so lets not include the headers.

Signed-off-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/humidity/dht11.c

···
 #include <linux/kernel.h>
 #include <linux/printk.h>
 #include <linux/slab.h>
-#include <linux/of.h>
-#include <linux/of_device.h>
 #include <linux/sysfs.h>
 #include <linux/io.h>
+#include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/wait.h>