hw/i386: Consolidate topology functions

Now that we have all the parameters in X86CPUTopoInfo, we can just
pass the structure to calculate the offsets and width.

Signed-off-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <158396717953.58170.5628042059144117669.stgit@naples-babu.amd.com>