cma: Add support for different size_cells and address_cells

Currently, the CMA flat device tree code does not take into account
targets that may specify size_cells and address_cells > 1. This will
lead to unsuccessful parsing. Add support for taking into account
nodes that may specify size_cells and address_cells explicitly.

Change-Id: I9ea63b8c34e903b186c29ec6555dd7a5c317c602
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>