cpu_ppc64.c: use typedefs for 'struct ppc64_vendor'
cpu_ppc64.c: use typedefs for 'struct ppc64_vendor'

Introduce virCPUppc64Vendor and virCPUppc64VendorPtr types to
improve code readability.

Signed-off-by: Daniel Henrique Barboza <627b089ad62deae9aaf06ccfa2c9056df28927e0@gmail.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>
Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

olafhering/libvirt,jfehlig/libvirt,nertpinx/libvirt,jfehlig/libvirt,jardasgit/libvirt,crobinso/libvirt,jardasgit/libvirt,jfehlig/libvirt,jardasgit/libvirt,libvirt/libvirt,crobinso/libvirt,zippy2/libvirt,nertpinx/libvirt,olafhering/libvirt,libvirt/libvirt,jardasgit/libvirt,nertpinx/libvirt,nertpinx/libvirt,libvirt/libvirt,libvirt/libvirt,jfehlig/libvirt,crobinso/libvirt,zippy2/libvirt,jardasgit/libvirt,zippy2/libvirt,crobinso/libvirt,nertpinx/libvirt,olafhering/libvirt,olafhering/libvirt,zippy2/libvirt