iio:trigger: add resource managed (un)register

Add resource managed devm_iio_trigger_register() and
devm_iio_triger_unregister() to automatically clean up registered triggers
allocated by IIO drivers, thus leading to simplified IIO drivers code.

Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index b0d775d..6a2138a 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -268,6 +268,8 @@
   devm_iio_kfifo_free()
   devm_iio_trigger_alloc()
   devm_iio_trigger_free()
+  devm_iio_trigger_register()
+  devm_iio_trigger_unregister()
   devm_iio_channel_get()
   devm_iio_channel_release()
   devm_iio_channel_get_all()