The iio_triggered_buffer_{predisable,postenable} functions attach/detach
the poll functions.

The iio_triggered_buffer_predisable() should be called last, to detach the
poll func after the devices has been suspended.

The position of iio_triggered_buffer_postenable() is correct.

Note this is not stable material. It's a fix in the logical
model rather fixing an actual bug.  These are being tidied up
throughout the subsystem to allow more substantial rework that
was blocked by variations in how things were done.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Acked-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>