crypto: caam - Enable and disable clocks on Freescale i.MX platforms

ARM-based systems may disable clocking to the CAAM device on the
Freescale i.MX platform for power management purposes.  This patch
enables the required clocks when the CAAM module is initialized and
disables the required clocks when the CAAM module is shut down.

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>