Interrupt type in FDT was interpreted incorrectly.
Patch taken from freebsd-arm thread 'GIC - interrupts interpretation in
DTS/FDT':
https://lists.freebsd.org/pipermail/freebsd-arm/2015-August/012145.html
Obtained from: Semihalf
Sponsored by: Stormshield
Submitted by: Michal Stanek <mst@semihalf.com>