iio:triggers: drop assign iio_info.driver_module and iio_trigger_ops.owner

The equivalent of both of these are now done via macro magic when
the relevant register calls are made.  The actual structure
elements will shortly go away.

Note that stm32-timer-trigger has expanded rather beyond triggers
(to include encoder input counting for example) and hence has an
iio_info structure.

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