Fix image build fail by using the generic subtarget. Fixes:cada395a("kirkwood: add generic subtarget") Ref:40e3f660("uboot-fritz4040: build with ipq40xx generic subtarget") Signed-off-by: Kuan-Yi Li <kyli@abysm.org> [ add commit description ] Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>