crypto: atmel-sha - add support for Device Tree

Add support for Device Tree and use of the DMA DT API to
get the channels if needed.
Documentation is added for these DT nodes.

Initial code by: Nicolas Royer and Eukrea.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>

Documentation/devicetree/bindings/crypto/atmel-crypto.txt

@@ -44,3 +44,25 @@ tdes@f803c000 {
 	       <&dma1 2 21>;
 	dma-names = "tx", "rx";
 };
+
+* Secure Hash Algorithm (SHA)
+
+Required properties:
+- compatible : Should be "atmel,at91sam9g46-sha".
+- reg: Should contain SHA registers location and length.
+- interrupts: Should contain the IRQ line for the SHA.
+
+Optional properties:
+- dmas: One DMA specifiers as described in
+        atmel-dma.txt and dma.txt files.
+- dma-names: Contains one identifier string for each DMA specifier
+             in the dmas property. Only one "tx" string needed.
+
+Example:
+sha@f8034000 {
+	compatible = "atmel,at91sam9g46-sha";
+	reg = <0xf8034000 0x100>;
+	interrupts = <42 4 0>;
+	dmas = <&dma1 2 17>;
+	dma-names = "tx";
+};