net/mlx5e: Fix spelling mistake "supoported" -> "supported"

There is a spelling mistake in a NL_SET_ERR_MSG_MOD error
message.  Fix it.

Fixes: 3b49a7ed ("net/mlx5e: TC, Reject rules with multiple CT actions")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>