firmware: qcom: ION changes to TZ log driver

ION kernel APIs are deprecated, change tz log
driver to use DMABUF APIs to do operations such
as mapping and cache maintenance.

Change-Id: I7d93d9c8e1ff379dd98cb9ceb0d62d3ccf145712
Signed-off-by: Zhen Kong <zkong@codeaurora.org>