msm: npu: Unload networks when driver handle is closed

If user process is killed during network execution, all related
networks need to be unloaded during driver handle is closed to avoid
resource leakage.

Change-Id: I993ef4bfdc11319ccf5bccda500814e143c0c316
Signed-off-by: Jilai Wang <jilaiw@codeaurora.org>