staging: iio: ad5933: fix format string warnings

Fixed the following warnings (reported by cppcheck):
[drivers/staging/iio/impedance-analyzer/ad5933.c:363]: (warning) %d in format string (no. 1)
requires 'int' but the argument type is 'unsigned int'.
[drivers/staging/iio/impedance-analyzer/ad5933.c:367]: (warning) %d in format string (no. 1)
requires 'int' but the argument type is 'unsigned int'.
[drivers/staging/iio/impedance-analyzer/ad5933.c:367]: (warning) %d in format string (no. 2)
requires 'int' but the argument type is 'unsigned int'.
[drivers/staging/iio/impedance-analyzer/ad5933.c:367]: (warning) %d in format string (no. 3)
requires 'int' but the argument type is 'unsigned int'.
[drivers/staging/iio/impedance-analyzer/ad5933.c:367]: (warning) %d in format string (no. 4)
requires 'int' but the argument type is 'unsigned int'.

Signed-off-by: Asaf Vertz <asaf.vertz@tandemg.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/impedance-analyzer/ad5933.c

@@ -360,11 +360,11 @@ static ssize_t ad5933_show(struct device *dev,
 	mutex_lock(&indio_dev->mlock);
 	switch ((u32) this_attr->address) {
 	case AD5933_OUT_RANGE:
-		len = sprintf(buf, "%d\n",
+		len = sprintf(buf, "%u\n",
 			      st->range_avail[(st->ctrl_hb >> 1) & 0x3]);
 		break;
 	case AD5933_OUT_RANGE_AVAIL:
-		len = sprintf(buf, "%d %d %d %d\n", st->range_avail[0],
+		len = sprintf(buf, "%u %u %u %u\n", st->range_avail[0],
 			      st->range_avail[3], st->range_avail[2],
 			      st->range_avail[1]);
 		break;