Add example writable passthrough configuration for firmware.
Add example writable passthrough configuration for firmware.

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