iio: fix iio_format_avail_range() printing for none IIO_VAL_INT

iio_format_avail_range() should print range as follow [min, step, max], so
the function was previously calling iio_format_list() with length = 3,
length variable refers to the array size of values not the number of
elements. In case of non IIO_VAL_INT values each element has integer part
and decimal part. With length = 3 this would cause premature end of loop
and result in printing only one element.

Signed-off-by: Fawzi Khaber <fawzi.khaber@tdk.com>
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Fixes: eda20ba1

 ("iio: core: Consolidate iio_format_avail_{list,range}()")
Link: https://lore.kernel.org/r/20220718130706.32571-1-jmaneyrol@invensense.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>