staging: ccree: add DT bus coherency detection

The ccree driver has build time configurable support
to work on top of coherent (e.g. ACP) vs. none coherent bus
connections. Turn it to run-time configurable option
based on device tree.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>