conf: replace virHostdevIsVFIODevice with virHostdevIsPCIDevice

conf: replace virHostdevIsVFIODevice with virHostdevIsPCIDevice

virHostdevIsVFIODevice() and virDomainDefHasVFIOHostdev() are only ever
called from the QEMU driver, and in the case of the QEMU driver, any
PCI hostdev by definition uses VFIO, so really all these callers only
need to know if the device is a PCI hostdev.

(It turned out that the less specific virHostdevIsPCIDevice() already
existed in hypervisor/virhostdev.c, so I had to remove one of them;
since conf is a lower level directory than hypervisor, and the
function is called from conf, keeping the copy in hypervisor would
have required moving its caller (virDomainDefHasPCIHostdev()) into
hypervisor as well, so I just removed the copy in hypervisor.)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>