mlxsw: core: Change BUG to WARN in hwmon code

Better to just warn the user that something really odd is going on and
continue to run.
Suggested-by: NOr Gerlitz <gerlitz.or@gmail.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c

@@ -215,7 +215,7 @@ static void mlxsw_hwmon_attr_add(struct mlxsw_hwmon *mlxsw_hwmon,
 			 "pwm%u", num + 1);
 		break;
 	default:
-		BUG();
+		WARN_ON(1);
 	}
 
 	mlxsw_hwmon_attr->type_index = type_index;