ARM: mvebu: Add thermal quirk for the Armada 375 DB board

The initial release of the Armada 375 DB board has an Armada 375
Z1 stepping silicon. This commit introduces a quirk that allows
to workaround a series of issues with the thermal sensor in this
stepping, but updating the devicetree:

  * Updates the compatible string for the thermal, so the driver
    can perform a specific initialization of the sensor.

  * Moves the offset of the thermal control register. This quirk
    allows to specifiy the correct (A0 stepping) offset in the
    devicetree.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Link: https://lkml.kernel.org/r/1398371004-15807-9-git-send-email-ezequiel.garcia@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>