Hi Jeremie,
I was able to build an app that contains a map fragment and an AdView (see screenshot). First, I'd recommend making sure your Gradle dependencies (ads, maps, and Play services) are in the same version number (for example, 8.4.0):
compile 'com.google.android.gms:play-services-ads:8.4.0'
compile 'com.google.android.gms:play-services-maps:8.4.0'
compile 'com.google.android.gms:play-services:8.4.0'
Then, leave your configChanges as is (i.e.
android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize"). The next steps should be self-explanatory (setting up a map fragment in your layout/code, and requesting the banner and your location).
Let us know if you have any questions,