power: reset: Add support for the new scm_call2 API

The SCM library now provides a new API that implements
a secure world syscall interface that is more aligned
with the ARMv8 SMC calling convention. Add support for
this new API.

Change-Id: Ia76309de556e97e43c1e8ab782f89c4115d5fac6
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>