iio: fix some warning messages

commit 231bfe53 upstream.

WARN_ON() only takes a condition argument.  I have changed these to
WARN() instead.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/iio/industrialio-buffer.c

@@ -753,7 +753,7 @@ int iio_scan_mask_set(struct iio_dev *indio_dev,
 	if (trialmask == NULL)
 		return -ENOMEM;
 	if (!indio_dev->masklength) {
-		WARN_ON("trying to set scanmask prior to registering buffer\n");
+		WARN(1, "trying to set scanmask prior to registering buffer\n");
 		goto err_invalid_mask;
 	}
 	bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);

drivers/iio/industrialio-core.c

@@ -567,7 +567,7 @@ int __iio_device_attr_init(struct device_attribute *dev_attr,
 					    chan->channel2,
 					    full_postfix);
 		else {
-			WARN_ON("Differential channels must be indexed\n");
+			WARN(1, "Differential channels must be indexed\n");
 			ret = -EINVAL;
 			goto error_free_full_postfix;
 		}