Staging: iio/dac/ad5064.c: signedness bug in ad5064_read_raw()

regulator_get_voltage() returns an int so "scale_uv" should be an
int.  Making it unsigned here breaks the error handling.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/dac/ad5064.c

@@ -280,8 +280,8 @@ static int ad5064_read_raw(struct iio_dev *indio_dev,
 			   long m)
 {
 	struct ad5064_state *st = iio_priv(indio_dev);
-	unsigned long scale_uv;
 	unsigned int vref;
+	int scale_uv;
 
 	switch (m) {
 	case 0: