qseecom: release ION memory if qseecom failed to unload app

To avoid memory leakage, make change to release ION memory if qseecom
failed to unload TZ app, which is allocated when starting app.

CRs-Fixed: 977073
Change-Id: Ic4c9a7d7a118ff5026ce6ce7769a4c053906ed2d
Signed-off-by: Zhen Kong <zkong@codeaurora.org>