staging:iio:docs: drop reference to setting trig_ops->owner

Whilst these docs have lots of other flaws, this element is definitely
no longer true.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

drivers/staging/iio/Documentation/trigger.txt

@@ -10,10 +10,6 @@ struct iio_trig *trig = iio_trigger_alloc("<trigger format string>", ...);
 allocates a trigger structure.  The key elements to then fill in within
 a driver are:
 
-trig->owner
-	Typically set to THIS_MODULE. Used to ensure correct
-	ownership of core allocated resources.
-
 trig->set_trigger_state:
 	Function that enables / disables the underlying source of the trigger.