s390x/cpumodel: introduce CPU feature group definitions

Let's use the generated groups to create feature group representations for
the user. These groups can later be used to enable/disable multiple
features in one shot and will be used to reduce the amount of reported
features to the user if all subfeatures are in place.

We want to work on features using ordinary bitmap operations, however we
can't initialize a bitmap statically (unsigned long[] ...). Therefore
we store the generated feature lists in separate arrays and convert
them to a proper bitmaps before they will ever be used.

Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Message-Id: <20160905085244.99980-8-dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
