arm64: dts: imx8-ss-conn: Move conn clocks outside of soc

The conn clock nodes do not have any register associated with it,
so they should be moved outside of soc to fix schema warning from
simple-bus.yaml.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>