Tack database growth rate modifications
Probably depends on how quickly you want to be alerted. 

If you just want to able to report on it then I'd probably suggest setting up a policy in Policy Based Management. You should be able to evaluate your instance on demand or on a schedule. You can generate an alert based off the SQL job it creates as well so you can be notified.

You could also look to just create a job that looked much like your query but either raise an error if there are databases that breach your policy (and append it to the alert)

The two options that would almost immediately let you know if someone had changed an autogrowth setting would be either via


DDL Server Scoped Trigger 
SQL Alert using WMI to query ALTER_DATABASE Events


However, the latter would probably need to use tokens and would definitely require Service Broker to be enabled on all databases to work.