net/mlx5: E-Switch, Allow setting GUID for host PF vport

E-switch should be able to set the GUID of host PF vport.
Currently it returns an error. This results in below error
when user attempts to configure MAC address of the PF of an
external controller.

$ devlink port function set pci/0000:03:00.0/196608 \
   hw_addr 00:00:00:11:22:33

mlx5_core 0000:03:00.0: mlx5_esw_set_vport_mac_locked:1876:(pid 6715):\
"Failed to set vport 0 node guid, err = -22.
RDMA_CM will not function properly for this VF."

Check for zero vport is no longer needed.

Fixes: 330077d1

 ("net/mlx5: E-switch, Supporting setting devlink port function mac address")
Signed-off-by: Yuval Avnery <yuvalav@nvidia.com>
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Bodong Wang <bodong@nvidia.com>
Reviewed-by: Alaa Hleihel <alaa@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>