msm: mink: uninitialized data in smcinvoke_release

uninitialized data in smcinvoke_release call is triggering a false
alarm to process piggyback data. This fix prevents this false
trigger case.

Change-Id: Id48333a7d4511ca7e67f8766dd9865c1f3868186
Signed-off-by: Dinesh K Garg <dineshg@codeaurora.org>