net/mlx5: Add hardware definitions for dump_fill_mkey

MLX5 IB HCA offers the memory key, dump_fill_mkey to boost
performance by forcing local HCA operations to skip the PCI bus
access,

This patch adds needed hardware definitions.
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

include/linux/mlx5/mlx5_ifc.h

@@ -885,7 +885,9 @@ struct mlx5_ifc_cmd_hca_cap_bits {
 	u8         log_max_eq_sz[0x8];
 	u8         reserved_at_e8[0x2];
 	u8         log_max_mkey[0x6];
-	u8         reserved_at_f0[0xc];
+	u8         reserved_at_f0[0x8];
+	u8         dump_fill_mkey[0x1];
+	u8         reserved_at_f9[0x3];
 	u8         log_max_eq[0x4];
 
 	u8         max_indirection[0x8];