The at86rf2xx chips supports the setting of irq polarity if active low
or active high. This patch adds a handling for IRQ_ACTIVE_LOW if the
irq_type is IRQ_TYPE_LEVEL_LOW.
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>