firmware: qcom: tz_log: 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.

Change-Id: I1fcf96b3a4ca55a7cd8c928d0f526250be5085bb
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: Zhen Kong <zkong@codeaurora.org>