devlink: Correct VIRTUAL port to not have phys_port attributes

devlink: Correct VIRTUAL port to not have phys_port attributes

Physical port name, port number attributes do not belong to virtual port
flavour. When VF or SF virtual ports are registered they incorrectly
append "np0" string in the netdevice name of the VF/SF.

Before this fix, VF netdevice name were ens2f0np0v0, ens2f0np0v1 for VF
0 and 1 respectively.

After the fix, they are ens2f0v0, ens2f0v1.

With this fix, reading /sys/class/net/ens2f0v0/phys_port_name returns
-EOPNOTSUPP.

Also devlink port show example for 2 VFs on one PF to ensure that any
physical port attributes are not exposed.

$ devlink port show
pci/0000:06:00.0/65535: type eth netdev ens2f0np0 flavour physical port 0 splittable false
pci/0000:06:00.3/196608: type eth netdev ens2f0v0 flavour virtual splittable false
pci/0000:06:00.4/262144: type eth netdev ens2f0v1 flavour virtual splittable false

This change introduces a netdevice name change on systemd/udev
version 245 and higher which honors phys_port_name sysfs file for
generation of netdevice name.

This also aligns to phys_port_name usage which is limited to switchdev
ports as described in [1].

[1] https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/tree/Documentation/networking/switchdev.rst

Fixes: c2e64a6eda75 ("devlink: Introduce devlink port flavour virtual")
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20210526200027.14008-1-parav@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>