arm64: dts: ls1088a: Move fsl-mc node

The fsl-mc node should sit under the soc node, so move it to
its proper location.

Fixes: ac7c9ff7 ("arm64: dts: ls1088a: add fsl-mc hardware resource manager node")
Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>