net/mlx5: Fix memory leak in bad flow of mlx5_alloc_irq_vectors

Fix a memory leak where in case that pci_alloc_irq_vectors failed,
priv->irq_info was not released.

Fixes: e126ba97 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: Alaa Hleihel <alaa@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>