hw/qdev: Consolidate qdev_get_printable_name() into qdev_get_human_name()

Rename qdev_get_printable_name() to qdev_get_human_name(), remove
the old qdev_get_human_name() implementation, and switch the three
qdev_get_printable_name() callers in hw/virtio/virtio.c.

qdev_get_printable_name() subsumes qdev_get_human_name(): both
return the device ID when set and fall back to the canonical QOM
path, but qdev_get_printable_name() also tries the bus-specific
path first, providing more informative output.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Alessandro Ratti <alessandro@0x65c.net>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Link: https://lore.kernel.org/r/20260321100405.1525059-4-alessandro@0x65c.net
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>