iio: adc: xilinx-ams: Fixed missing PS channels

The code forgot to increment num_channels for the PS channel inputs,
resulting in them not being enabled as they should.

Fixes: d5c70627 ("iio: adc: Add Xilinx AMS driver")
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Reviewed-by: Michael Tretter <m.tretter@pengutronix.de>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/20220127173450.3684318-3-robert.hancock@calian.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/xilinx-ams.c

@@ -1225,6 +1225,7 @@ static int ams_init_module(struct iio_dev *indio_dev,
 
 		/* add PS channels to iio device channels */
 		memcpy(channels, ams_ps_channels, sizeof(ams_ps_channels));
+		num_channels = ARRAY_SIZE(ams_ps_channels);
 	} else if (fwnode_property_match_string(fwnode, "compatible",
 						"xlnx,zynqmp-ams-pl") == 0) {
 		ams->pl_base = fwnode_iomap(fwnode, 0);