iio: Fix typos in ABI documentation

Fix typos in ABI documentation
Signed-off-by: NVladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Documentation/ABI/testing/sysfs-bus-iio

@@ -503,9 +503,9 @@ Description:
 		outX_powerdown_mode_available. If Y is not present the
 		mode is shared across all outputs.
 
-What:		/sys/.../iio:deviceX/out_votlageY_powerdown_mode_available
+What:		/sys/.../iio:deviceX/out_voltageY_powerdown_mode_available
 What:		/sys/.../iio:deviceX/out_voltage_powerdown_mode_available
-What:		/sys/.../iio:deviceX/out_altvotlageY_powerdown_mode_available
+What:		/sys/.../iio:deviceX/out_altvoltageY_powerdown_mode_available
 What:		/sys/.../iio:deviceX/out_altvoltage_powerdown_mode_available
 KernelVersion:	2.6.38
 Contact:	linux-iio@vger.kernel.org