iio: light: bu27008: Fix intensity data type

The intensity data from bu27008 is unsigned. The type of the scan data
was incorrectly marked as signed resulting large intensity values to be
interpreted as negative ones.

Fix the scan data type.

Fixes: 41ff93d ("iio: light: ROHM BU27008 color sensor")
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/240a7ca5fc1b76da20d81f930d00f31a54b1fdf8.1686648422.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: M-Vaittinen

drivers/iio/light/rohm-bu27008.c

@@ -190,7 +190,7 @@ static const struct iio_itime_sel_mul bu27008_itimes[] = {
 	.address = BU27008_REG_##data##_LO,					\
 	.scan_index = BU27008_##color,						\
 	.scan_type = {								\
-		.sign = 's',							\
+		.sign = 'u',							\
 		.realbits = 16,							\
 		.storagebits = 16,						\
 		.endianness = IIO_LE,						\