MSM Shared memory driver

msm-shared-memory driver is responsible for calling into the secure environemnt
to allow clients to use the HLOS memory that is assigned to them, which is
locked by the secure world.

Required Properties for shared memory:
- compatible:		   Must be "qcom,msm-shared-memory"
- qcom,proc-id :	   The id of the processor that needs access to the
			   HLOS memory
- linux,contiguous-region: phandle reference to a CMA region.

Example:
	adsp_heap {
		compatible = "qcom,msm-shared-memory";
		qcom,proc-id = <1>;
		linux,contiguous-region = <&adsp_mem>;
	};