net/mlx5: Reuse exported virtfn index function call

Instead open-code iteration to compare virtfn internal index, use newly
introduced pci_iov_vf_id() call.

Link: https://lore.kernel.org/all/20220224142024.147653-3-yishaih@nvidia.comSigned-off-by: NYishai Hadas <yishaih@nvidia.com>
Signed-off-by: NLeon Romanovsky <leonro@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/sriov.c

@@ -205,19 +205,8 @@ int mlx5_core_sriov_set_msix_vec_count(struct pci_dev *vf, int msix_vec_count)
 			mlx5_get_default_msix_vec_count(dev, pci_num_vf(pf));
 
 	sriov = &dev->priv.sriov;
-
-	/* Reversed translation of PCI VF function number to the internal
-	 * function_id, which exists in the name of virtfn symlink.
-	 */
-	for (id = 0; id < pci_num_vf(pf); id++) {
-		if (!sriov->vfs_ctx[id].enabled)
-			continue;
-
-		if (vf->devfn == pci_iov_virtfn_devfn(pf, id))
-			break;
-	}
-
-	if (id == pci_num_vf(pf) || !sriov->vfs_ctx[id].enabled)
+	id = pci_iov_vf_id(vf);
+	if (id < 0 || !sriov->vfs_ctx[id].enabled)
 		return -EINVAL;
 
 	return mlx5_set_msix_vec_count(dev, id + 1, msix_vec_count);