net/mgmt: Mask vs event should be verified part by part

It needs to check if current event matches:

- cb's layer
- cb's layer code
- cb's command

If none match, it will not raise the event.

Fixing the unit test as layer must be always != 0.

Jira: ZEP-1940

Change-Id: Iadd63e751fa6e534a10e7da9cae0f5bb5a384461
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>