cma: Change to reserve-contiguous-region

Currently, devices are associated with CMA regions via phandle to the
CMA region. The phandle name 'linux,contiguous-region' is the same as
that which is used to designate a CMA region. This can lead to issues
of trying to treat a device only using a CMA region as an actual CMA
region. Rather than continuing to rely on this handle and the depth
to differentiate CMA regions, just create separate DT binding
linux,reserve-contiguous-region to indicate that the node is
an actual CMA node for reserving rather than a client referencing
via phandle.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
ARM: dts: msm: Move audio heaps over to use reserved CMA
 regions

Carveout regions are being deprecated. Convert the audio heaps over
to use a reserved CMA region instead of a carveout. At a later time,
the audio regions may be converted over to a fully functional CMA region.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
[neo: Use increased ion heap size for better 5.1 AAC playback]
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>

Conflicts:
	arch/arm/boot/dts/msm8974-ion.dtsi