drivers: Add option to reserve default CMA region

CMA provides good utilization of memory but for some use cases, the
allocation time is too costly. Add a Kconfig option to allow the
default region to be permanently set aside for contiguous use cases.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
cma: print physical addresses correctly

Physical addresses can be greater than an unsigned long on
systems with LPAE. Print these addresses properly with %pa

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>