qseecom: fix memory leak in qseecom_start_app()

Fixes the incorrect return path in qseecom_start_app() function with
proper clean-up. With out this patch, there are lot of memory leaks.

Change-Id: Ied95480fa28b11efa3e53219102bfbe782921351
Signed-off-by: AnilKumar Chimata <anilc@codeaurora.org>