The CPU driver provides APIs to create and free virCPUDataPtr. Thus all
APIs exported from the driver should work with that rather than
requiring the caller to pass a pointer to an internal part of the
structure.

In other words

    virCPUx86DataAddCPUID(cpudata, &cpuid)

is much better than the original

    virCPUx86DataAddCPUID(&cpudata->data.x86, &cpuid)
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>