pcie: Specify 0 for ARI next function numbers

pcie: Specify 0 for ARI next function numbers

The current implementers of ARI are all SR-IOV devices. The ARI next
function number field is undefined for VF according to PCI Express Base
Specification Revision 5.0 Version 1.0 section 9.3.7.7. The PF still
requires some defined value so end the linked list formed with the field
by specifying 0 as required for any ARI implementation according to
section 7.8.7.2.

For migration, the field will keep having 1 as its value on the old
QEMU machine versions.

Fixes: 2503461691 ("pcie: Add some SR/IOV API documentation in docs/pcie_sriov.txt")
Fixes: 44c2c09488 ("hw/nvme: Add support for SR-IOV")
Fixes: 3a977deebe ("Intrdocue igb device emulation")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Message-Id: <20230710153838.33917-3-akihiko.odaki@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>