net/mlx5: SF: Fix error flow of SFs allocation flow

When SF id is unavailable, code jumps to wrong label that accesses
sw id array outside of its range.
Hence, when SF id is not allocated, avoid accessing such array.

Fixes: 8f010541 ("net/mlx5: SF, Add port add delete functionality")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>