qseecom: Fix kernel panic

When qseecom_unload_app() is invoked, wait_event_freezable() is called
in an atomic context (within a spinlock).  wait_event_freezable() allows
sleep and should not  be called in an atomic context where sleep is not
allowed.

Change-Id: I8c9c6d28f9e492fbbf2ac74a5ee3d1067c7733ad
Signed-off-by: Mona Hossain <mhossain@codeaurora.org>