IB/mlx5: Fix undefined behavior due to shift overflowing the constant

Fix:

  drivers/infiniband/hw/mlx5/main.c: In function ‘translate_eth_legacy_proto_oper’:
  drivers/infiniband/hw/mlx5/main.c:370:2: error: case label does not reduce to an integer constant
    case MLX5E_PROT_MASK(MLX5E_50GBASE_KR2):
    ^~~~

See https://lore.kernel.org/r/YkwQ6%2BtIH8GQpuct@zn.tnic for the gory
details as to why it triggers with older gccs only.

Link: https://lore.kernel.org/all/20220405151517.29753-11-bp@alien8.deSigned-off-by: Borislav Petkov <bp@suse.de>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Saeed Mahameed <saeedm@nvidia.com>
Cc: linux-rdma@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>

include/linux/mlx5/port.h

@@ -141,7 +141,7 @@ enum mlx5_ptys_width {
 	MLX5_PTYS_WIDTH_12X	= 1 << 4,
 };
 
-#define MLX5E_PROT_MASK(link_mode) (1 << link_mode)
+#define MLX5E_PROT_MASK(link_mode) (1U << link_mode)
 #define MLX5_GET_ETH_PROTO(reg, out, ext, field)	\
 	(ext ? MLX5_GET(reg, out, ext_##field) :	\
 	MLX5_GET(reg, out, field))