Documentation: iio-trig-sysfs: Document add_trigger attribute

This patch adds the ABI documentation for the add_trigger
attribute, which is provided by the iio-trig-sysfs stand-alone driver.

Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
1 file changed