qseecom: Support multiple clients.

When multiple clients request qseecom to load an application, an app
id is assigned. If the request is to load an app that already exists
in qsee, the app id should return to the qseecom library.
Returning the app id was done in the qseecom_load_app() but not done
in the qseecom_query_app_loaded(). This change fixes the issue when
multiple clients request to load the same app in qsee.

Change-Id: Icaa5053906b61ace1d257ff1c96308cc89e3a9cc
Signed-off-by: Ramesh Masavarapu <rameshm@codeaurora.org>