msm: pil-q6v5-lpass: Add support for secure image loading

Use the scm-pas APIs to authenticate and securely boot signed images
when supported. This is very similar to secure peripheral support
present in previous PIL drivers.

Change-Id: I3b6be69ad2f30ff5ba8c5de93051276936a1ab44
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>