[qca-nss-ecm] Ensure the message sent to nss-drv is returned before module exit

If we sent a stats request message down to NSS, we need to ensure the returned
message is received before we exit, otherwise if the message returns late, NSS
might call the callback func in ECM but ECM is already removed at that time.

Change-Id: I13e3fa9f4a829c3275a888e9984a8b1cf3e1ce06
Signed-off-by: Stephen Wang <wstephen@codeaurora.org>
2 files changed