iio: example code is buggy

Shock horror, example template code that has never been used in reality is
in fact a hazard. This fixes the obvious bug, probably these kind of
"examples" should be deleted so real (working) examples are followed.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>