msm: npu: Support multiple execution_network commands per network

This change is to allow application to submit multiple
execution_network commands for the same network concurrently to
NPU fw in order to fully utilize NPU's processing power.

Change-Id: Ide5293d8a779ff17038169db2a3b1c862c453296
Signed-off-by: Jilai Wang <jilaiw@codeaurora.org>