net/mlx5: E-Switch, Properly refer to host PF vport as other vport

Commands referring to vports use the following scheme:

1. When referring to my own vport, put 0 in vport and 0 in other_vport.
2. When referring to another vport, put the vport number of the
   referred vport and put 1 in other_vport. It was assumed that driver
   is accessing other vport when vport number is greater than 0.

With the above scheme, the case that ECPF eswitch manager is trying
to access host PF vport will fall over with scheme 1 as the vport
number is 0. This is apparently wrong as driver is trying to refer
other vport.

As such usage can only happen in the eswitch context, change relevant
functions to provide other vport input properly.

Signed-off-by: Bodong Wang <bodong@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>