crypto: caam - Add cache coherency support

Freescale i.MX6 ARM platforms do not support hardware cache coherency.
This patch adds cache coherency support to the CAAM driver.

Signed-off-by: Victoria Milhoan <vicki.milhoan@freescale.com>
Tested-by: Horia Geantă <horia.geanta@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>