The bootargs line is already commented out and the comment of UART4
does not apply, as uart4 node is not described.

Remove both comments to make the dtsi cleaner.
Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>