iio: ABI: Add a new location label

Add "accel-camera" when an IMU is location near the camera in a swivel
sub-assembly. These IMU are used for AR applications.
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Link: https://lore.kernel.org/r/20220427190804.961697-2-gwendal@chromium.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/ABI/testing/sysfs-bus-iio

@@ -79,6 +79,11 @@ Description:
 		* "accel-base"
 		* "accel-display"
 
+		For devices where an accelerometer is housed in the swivel camera subassembly
+		(for AR application), the following standardized label is used:
+
+		* "accel-camera"
+
 What:		/sys/bus/iio/devices/iio:deviceX/current_timestamp_clock
 KernelVersion:	4.5
 Contact:	linux-iio@vger.kernel.org