MLK-10897-1 ARM: imx7d: Add CAAM support for i.mx7d

MLK-10897-1 ARM: imx7d: Add CAAM support for i.mx7d

CAAM only has a single clock in i.mx7d. Logic was added to initialize only the
single clock.

The Secure Memory registers moved in CAAM era included in i.mx7d. This required
changes to support access to two different versions of the register map. The
registers are access through a data structure that overlay the register region.
Two new Secure Memory register structures were created to support the different
versions. Logic was also added to determine which version is implemented based on
the CAAM era, and access functions were added to support register access to the
Secure Memory Command and Status registers.

Signed-off-by: Dan Douglass <dan.douglass@freescale.com>