crypto: dcp - Added support for Freescale's DCP co-processor

This patch enables the DCP crypto functionality on imx28.
Currently, only aes-128-cbc is supported.
Moreover, the dcpboot misc-device, which is used by Freescale's
SDK tools and uses a non-software-readable OTP-key, is added.

Changes of v2:
- ring buffer for hardware-descriptors
- use of ablkcipher walk
- OTP key encryption/decryption via misc-device
  (compatible to Freescale-SDK)
- overall cleanup

The DCP is also capable of sha1/sha256 but I won't be able to add
that anytime soon.
Tested with built-in runtime-self-test, tcrypt and openssl via
cryptodev 1.6 on imx28-evk and a custom built imx28-board.

Signed-off-by: Tobias Rauter <tobias.rauter@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
index 600f7cb..077d0eb 100644
--- a/arch/arm/boot/dts/imx28.dtsi
+++ b/arch/arm/boot/dts/imx28.dtsi
@@ -699,7 +699,7 @@
 			dcp@80028000 {
 				reg = <0x80028000 0x2000>;
 				interrupts = <52 53 54>;
-				status = "disabled";
+				compatible = "fsl-dcp";
 			};
 
 			pxp@8002a000 {