kvm: Common device control API functions

kvm: Common device control API functions

Introduces two simple functions:
    int kvm_device_ioctl(int fd, int type, ...);
    int kvm_create_device(KVMState *s, uint64_t type, bool test);

These functions wrap the basic ioctl-based interactions with KVM in a
way similar to other KVM ioctl wrappers.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Message-id: 1392687720-26806-4-git-send-email-christoffer.dall@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>