s390x/cpumodel: mepochptff: warn when no mepoch and re-align group init

s390x/cpumodel: mepochptff: warn when no mepoch and re-align group init

The extended PTFF features (qsie, qtoue, stoe, stoue) are dependent
on the multiple-epoch facility (mepoch). Let's print a warning if these
features are enabled without mepoch.

While we're at it, let's move the FEAT_GROUP_INIT for mepochptff down
the s390_feature_groups list so it can be properly indexed with its
generated S390FeatGroup enum.

Signed-off-by: Collin Walling <[email protected]>
Message-Id: <20190212011657[email protected]>
Reviewed-by: Christian Borntraeger <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Signed-off-by: Cornelia Huck <[email protected]>