[POWERPC] Introduce new CPM device bindings.

This introduces a new device binding for the CPM and other devices on
these boards.  Some of the changes include:

1. Proper namespace scoping for Freescale compatibles and properties.

2. Use compatible rather than things like device_type and model
to determine which particular variant of a device is present.

3. Give the drivers the relevant CPM command word directly, rather than
requiring it to have a lookup table based on device-id, SCC v. SMC, and
CPM version.

4. Specify the CPCR and the usable DPRAM region in the CPM's reg property.

Boards that do not require the legacy bindings should select
CONFIG_PPC_CPM_NEW_BINDING to enable the of_platform CPM devices. Once
all existing boards are converted and tested, the config option can
become default y to prevent new boards from using the old model.  Once
arch/ppc is gone, the config option can be removed altogether.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>