iio: adc: ad7923: Fix checkpatch warning

Fix checkpatch warning:
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
+static int ad7923_scan_direct(struct ad7923_state *st, unsigned ch)
Signed-off-by: Daniel Junho <djunho@gmail.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7923.c

@@ -184,7 +184,7 @@ static irqreturn_t ad7923_trigger_handler(int irq, void *p)
 	return IRQ_HANDLED;
 }
 
-static int ad7923_scan_direct(struct ad7923_state *st, unsigned ch)
+static int ad7923_scan_direct(struct ad7923_state *st, unsigned int ch)
 {
 	int ret, cmd;