ARM: dts: vf610-zii-scu4-aib: Remove internal debug network interfaces

"internal_j8" and "internal_j9" are network interfaces that are not
exposed outside the board and were only ever used for debugging purposes.

Get rid of them as they are not needed.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>