iio:dac:ad5446: Drop of_match_ptr and CONFIG_OF protections

These prevent use of this driver with ACPI via PRP0001 and are
an example of an anti pattern I'm trying to remove from IIO.
Hence drop them from this driver.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Link: https://lore.kernel.org/r/20200910173242.621168-10-jic23@kernel.org

drivers/iio/dac/ad5446.c

@@ -17,6 +17,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/err.h>
 #include <linux/module.h>
+#include <linux/mod_devicetable.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -478,13 +479,11 @@ static const struct spi_device_id ad5446_spi_ids[] = {
 };
 MODULE_DEVICE_TABLE(spi, ad5446_spi_ids);
 
-#ifdef CONFIG_OF
 static const struct of_device_id ad5446_of_ids[] = {
 	{ .compatible = "ti,dac7512" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ad5446_of_ids);
-#endif
 
 static int ad5446_spi_probe(struct spi_device *spi)
 {
@@ -502,7 +501,7 @@ static int ad5446_spi_remove(struct spi_device *spi)
 static struct spi_driver ad5446_spi_driver = {
 	.driver = {
 		.name	= "ad5446",
-		.of_match_table = of_match_ptr(ad5446_of_ids),
+		.of_match_table = ad5446_of_ids,
 	},
 	.probe		= ad5446_spi_probe,
 	.remove		= ad5446_spi_remove,