crypto: add i.MX6 CAAM support ...

Add the i.MX6 crypto core CAAM with support for the random number
generator.

The core itself works with jobrings in which descriptors can be
queued/dequeued for processing. Depending on descriptor type
the CAAM unit then either produces random numbers or decrypts/encrypts
data.

The code is based on the Linux v4.1 driver of the same name
without all the crypto/hashing components.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>