ARM: mvebu: Add RTC support for Armada 375

The Armada 375 SoC has the same real time clock as the one used in
other Marvell EBU platforms. This patch consequently updates the
Device Tree of the Armada 375 SoC to describe the internal RTC.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1406817122-15675-1-git-send-email-gregory.clement@free-electrons.com


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