net/mlx5: Fix masking of reserved bits in XRCD number

BugLink: https://bugs.launchpad.net/bugs/1878232

commit 9cd3411c upstream.

Mask the reserved bits when reading the number of newly
created XRCD.

Fixes: e126ba97 ('mlx5: Add driver for Mellanox Connect-IB adapters')
Signed-off-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

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

@@ -393,7 +393,7 @@ int mlx5_core_xrcd_alloc(struct mlx5_core_dev *dev, u32 *xrcdn)
 	if (out.hdr.status)
 		err = mlx5_cmd_status_to_err(&out.hdr);
 	else
-		*xrcdn = be32_to_cpu(out.xrcdn);
+		*xrcdn = be32_to_cpu(out.xrcdn) & 0xffffff;
 
 	return err;
 }