Add missing import, required with gnu-arm-embedded.
Add missing import, required with gnu-arm-embedded.

ene-ilies/vi-firmware,openxc/vi-firmware,mgiannikouris/vi-firmware,mgiannikouris/vi-firmware,openxc/vi-firmware,openxc/vi-firmware,openxc/vi-firmware,ene-ilies/vi-firmware,ene-ilies/vi-firmware,mgiannikouris/vi-firmware,mgiannikouris/vi-firmware,ene-ilies/vi-firmware