net/mlx5: prevent memory leak in mlx5_fpga_conn_create_cq

In mlx5_fpga_conn_create_cq if mlx5_vector2eqn fails the allocated
memory should be released.

Fixes: 537a5057

 ("net/mlx5: FPGA, Add high-speed connection routines")
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>