RDMA/mlx5: Fix port number for counter query in multi-port configuration

Set the correct port when querying PPCNT in multi-port configuration.
Distinguish between cases where switchdev mode was enabled to multi-port
configuration and don't overwrite the queried port to 1 in multi-port
case.

Fixes: 74b30b3a

 ("RDMA/mlx5: Set local port to one when accessing counters")
Signed-off-by: Michael Guralnik <michaelgur@nvidia.com>
Link: https://lore.kernel.org/r/9bfcc8ade958b760a51408c3ad654a01b11f7d76.1712134988.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>