ARM: mvebu: Add a 2 GHz fixed-clock on Armada 38x SoCs

Armada 38x SoCs have a 2 GHz fixed main PLL that is used to feed
other clocks. This commit adds a DT representation of this clock
through a fixed-clock compatible node.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Link: https://lkml.kernel.org/r/1394742273-5113-3-git-send-email-ezequiel.garcia@free-electrons.com


Signed-off-by: Jason Cooper <jason@lakedaemon.net>