RDMA/mlx5: Remove not-used IB_FLOW_SPEC_IB define

IB_FLOW_SPEC_IB is not used in mlx5 and can be deleted.
Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Link: https://lore.kernel.org/r/20221208101954.687960-1-yanjun.zhu@intel.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/mlx5/fs.c

@@ -127,7 +127,6 @@ static int check_mpls_supp_fields(u32 field_support, const __be32 *set_mask)
 }
 
 #define LAST_ETH_FIELD vlan_tag
-#define LAST_IB_FIELD sl
 #define LAST_IPV4_FIELD tos
 #define LAST_IPV6_FIELD traffic_class
 #define LAST_TCP_UDP_FIELD src_port