iio:dac:ti-dac5571: Drop of_match_ptr and CONFIG_OF protections

These prevent the 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: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Link: https://lore.kernel.org/r/20200910173242.621168-16-jic23@kernel.org

drivers/iio/dac/ti-dac5571.c

@@ -18,8 +18,7 @@
 #include <linux/iio/iio.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
-#include <linux/of_device.h>
-#include <linux/of.h>
+#include <linux/mod_devicetable.h>
 #include <linux/regulator/consumer.h>
 
 enum chip_id {
@@ -384,7 +383,6 @@ static int dac5571_remove(struct i2c_client *i2c)
 	return 0;
 }
 
-#ifdef CONFIG_OF
 static const struct of_device_id dac5571_of_id[] = {
 	{.compatible = "ti,dac5571"},
 	{.compatible = "ti,dac6571"},
@@ -398,7 +396,6 @@ static const struct of_device_id dac5571_of_id[] = {
 	{}
 };
 MODULE_DEVICE_TABLE(of, dac5571_of_id);
-#endif
 
 static const struct i2c_device_id dac5571_id[] = {
 	{"dac5571", single_8bit},
@@ -417,7 +414,7 @@ MODULE_DEVICE_TABLE(i2c, dac5571_id);
 static struct i2c_driver dac5571_driver = {
 	.driver = {
 		   .name = "ti-dac5571",
-		   .of_match_table = of_match_ptr(dac5571_of_id),
+		   .of_match_table = dac5571_of_id,
 	},
 	.probe	  = dac5571_probe,
 	.remove   = dac5571_remove,