msm: ADSPRPC: change fastrpc driver to support legacy chipsets

Set legacy flag if device node has qcom,msm-fastrpc-legacy-compute
attribute. Assign CMA base address and CMA size before doing CMA
memory protection.

Change-Id: Id457f5b0808d3c60ac8a2c7ef90866d82d46e935
Acked-by: Chenna Kesava Raju <chennak@qti.qualcomm.com>
Signed-off-by: Tharun Kumar Merugu <mtharu@codeaurora.org>