arm64: dts: imx8mp: add NoC node

Add i.MX8MP NoC node to make the interconnect i.MX8MP driver could work.
Currently dynamic frequency scaling of the i.MX8MP NoC has not been
supported, only NoC initial settings are configured by interconnect
driver.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Acked-by: Georgi Djakov <djakov@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>