ion: msm : secure_buffer: Add support for the new scm_call2 API

The scm library has added support for a new secure world
interface that is more aligned to the ARMv8 SMC calling
convention. Use the new API while maintaining backward
compatibility for the mem-protect call.

Change-Id: I3a4432f2eab4c52d0fb2e8aa5d5e9dd650fd05ef
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>