iio:adc:max11100: Drop of_match_ptr protection / add mod_devicetable.h include

Allows use of driver with ACPI PRP0001 base binding.
Mostly this is about trying to avoid cut and paste of this into new
drivers (it is a frequent review comment) rather than any
thought that this driver might get used on an ACPI platform.

The mod_devicetable.h include is to encourage best practice of including
any header directly used within the code (here for of_match_id)
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

drivers/iio/adc/max11100.c

@@ -8,6 +8,7 @@
  */
 #include <linux/delay.h>
 #include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>
@@ -161,7 +162,7 @@ MODULE_DEVICE_TABLE(of, max11100_ids);
 static struct spi_driver max11100_driver = {
 	.driver = {
 		.name	= "max11100",
-		.of_match_table = of_match_ptr(max11100_ids),
+		.of_match_table = max11100_ids,
 	},
 	.probe		= max11100_probe,
 	.remove		= max11100_remove,