msm: cachedump: Add cache maintenance for calls into TZ

The scm_call API is no longer providing implicit cache maintenance for
shared buffers. Add cache flushing for buffers heading towards TZ and
cache invalidation for buffers coming from TZ.

Change-Id: Iaafdc10ee49b43f462ba00dd751861a3b285a067
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>