qemu_hotplug: remove unnecessary check for valid PCI address

qemu_hotplug: remove unnecessary check for valid PCI address

When support for hotplug/unplug of SCSI controllers was added way back
in December 2009 (commit da9d937b), unplug was handled by calling the
now-extinct function qemuMonitorRemovePCIDevice(), which required a
PCI address as an argument. At the same time, the idea of every device
in the config having a PCI address apparently was not yet fully
implemented, because the author of the patch including a check for a
valid PCI address in the device object.

These days, all PCI devices are guaranteed to have a valid PCI
address. But more important than that, we no longer detach devices by
PCI address, but instead use qemuDomainDeleteDevice(), which
identifies the device by its alias. So checking for a valid PCI
address is just pointless extra code that obscures the high level of
similarity between all the individual qemuDomainDetach*Device()
functions.

Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>