ARM: mvebu: Relocate PCIe node in Armada 370 RD board

The pcie-controller node needs to be relocated according the MBus
DT binding, since it's now a child of the mbus-compatible node.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>