soc: qcom: glink_smem: Initialize buffers

Zero initialize the local variables that store information from the
remote. On the chance reading from the remote fails, the data in these
structs will now be zero instead of stale data.

Change-Id: Iafaeb71a5dc57e27a34b4250ea529fbe27df2393
Signed-off-by: Chris Lew <clew@codeaurora.org>