Fix syntax error in makefile.
Fix syntax error in makefile.

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