dt-bindings: iio: st: Remove wrong items length check

The original bindings was listing the length of the interrupts as either
1 or 2, depending on the setup. This is also what is enforced by the top
level schema.

However, that is further constrained with an if clause that require
exactly two interrupts, even though it might not make sense on those
devices or in some setups.

Let's remove the clause entirely.

Cc: Denis Ciocca <denis.ciocca@st.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Fixes: 0cd71145 ("iio: st-sensors: Update ST Sensor bindings")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210721140424.725744-16-maxime@cerno.tech


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>