arm64: dts: imx8mp: Move funnel outside from soc

The 'funnel' node does not contain a register range, so it should
be placed outside of the soc node to fix schema warnings from
simple-bus.yaml.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Acked-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>