soc: qcom: memory_dump_v2: Fixup core debug unlock and support ARMv8 scm

Use the right command ID for the core-debug-unlock scm_call
and add support for the new scm_call2 API. This new API
is more aligned to the ARMv8 SMC calling convention.

Change-Id: Ida76f2dc5ea67066e49ffe1e0e04c2056134f381
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>