dt-bindings: fix incorrect bmi160 IRQ note

The bmi160 bindings say that the BMI160 requires level-triggered,
active-low interrupts, but it actually supports all interrupt types, so fix
the note to reflect that.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Martin Kelly <martin@martingkelly.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>