ARM: at91/soc: add basic support for new sama5d2 SoC

Add Kconfig entries, header file changes and addition to the documentation.
The early debug infrastructure is also added for easy development.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
diff --git a/Documentation/devicetree/bindings/arm/atmel-at91.txt b/Documentation/devicetree/bindings/arm/atmel-at91.txt
index 424ac8c..7f04b8a 100644
--- a/Documentation/devicetree/bindings/arm/atmel-at91.txt
+++ b/Documentation/devicetree/bindings/arm/atmel-at91.txt
@@ -27,6 +27,8 @@
     o "atmel,at91sam9xe"
  * "atmel,sama5" for SoCs using a Cortex-A5, shall be extended with the specific
    SoC family:
+    o "atmel,sama5d2" shall be extended with the specific SoC compatible:
+       - "atmel,sama5d27"
     o "atmel,sama5d3" shall be extended with the specific SoC compatible:
        - "atmel,sama5d31"
        - "atmel,sama5d33"