s390x: css: testing measurement block format 1

Measurement block format 1 is made available by the extended
measurement block facility and is indicated in the SCHIB by
the bit in the PMCW.

The MBO is specified in the SCHIB of each channel and the MBO
defined by the SCHM instruction is ignored.

The test of the MB format 1 is just skipped if the feature is
not available.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Link: https://lore.kernel.org/kvm/1615545714-13747-7-git-send-email-pmorel@linux.ibm.com/


Signed-off-by: Janosch Frank <frankja@linux.ibm.com>