nvme: don't reject probe due to duplicate IDs for single-ported PCIe devices

While duplicate IDs are still very harmful, including the potential to easily
see changing devices in /dev/disk/by-id, it turn out they are extremely
common for cheap end user NVMe devices.

Relax our check for them for so that it doesn't reject the probe on
single-ported PCIe devices, but prints a big warning instead.  In doubt
we'd still like to see quirk entries to disable the potential for
changing supposed stable device identifier links, but this will at least
allow users how have two (or more) of these devices to use them without
having to manually add a new PCI ID entry with the quirk through sysfs or
by patching the kernel.

Fixes: 2079f41e ("nvme: check that EUI/GUID/UUID are globally unique")
Cc: stable@vger.kernel.org # 6.0+
Co-developed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>