staging: ccree: add DT bindings for Arm CryptoCell

This adds DT bindings for the Arm TrustZone CryptoCell cryptographic
accelerator IP.

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