Excludes firmware pkg detected on rhel7
Excludes firmware pkg detected on rhel7

Failures appear to be caused by an obselete marker, since the
required pkg `iwl7260-firmware` is already excluded

```
    minimal-rhel-7-hvm: Package iwl7265-firmware is obsoleted by iwl7260-firmware, trying to install iwl7260-firmware-25.30.13.0-76.el7.noarch instead
```

ferricoxide/AMIgen7