adsprpc:Make TZ security skel call for DSP backward compatible

First make skel call to DSP with new method ID for getting
the TZ security key, if it fails, make call to DSP
with old method ID to make compatible to all chipsets.

Change-Id: I89663a50e27cdfb73e2c919235c44ec2643fc159
Acked-by: Tadakamalla Krishnaiah <ktadakam@qti.qualcomm.com>
Signed-off-by: Mohammed Nayeem Ur Rahman <mohara@codeaurora.org>