qemu: change the logic of setting default USB controller
qemu: change the logic of setting default USB controller

The new logic will set the piix3-uhci if available regardless of
any architecture and it will be updated to better model based on
architecture and device existence.

Signed-off-by: Pavel Hrdina <d4772d05997b8abf035041e3b4f4996380ea7e7a@redhat.com>
Acked-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>

eskultety/libvirt,datto/libvirt,libvirt/libvirt,andreabolognani/libvirt,datto/libvirt,jardasgit/libvirt,nertpinx/libvirt,jardasgit/libvirt,jfehlig/libvirt,jfehlig/libvirt,nertpinx/libvirt,olafhering/libvirt,eskultety/libvirt,nertpinx/libvirt,libvirt/libvirt,jfehlig/libvirt,VenkatDatta/libvirt,crobinso/libvirt,andreabolognani/libvirt,datto/libvirt,zippy2/libvirt,zippy2/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,nertpinx/libvirt,andreabolognani/libvirt,eskultety/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,libvirt/libvirt,jardasgit/libvirt,datto/libvirt,eskultety/libvirt,olafhering/libvirt,olafhering/libvirt,datto/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,crobinso/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,zippy2/libvirt,olafhering/libvirt,eskultety/libvirt,jfehlig/libvirt,nertpinx/libvirt,crobinso/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,crobinso/libvirt,libvirt/libvirt,zippy2/libvirt,VenkatDatta/libvirt