726c609936
Allow boards to use the device creation functions even if USB itself is not available; of course the functions will fail inexorably, but this can be okay if the calls are conditional on the existence of some USB host controller device. This is for example the case for hw/mips/loongson3_virt.c. Acked-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>