s390/cpum_cf: add hardware counter support for IBM z14

Add the hardware counters that are available with z14.  With z14,
the number of problem-state counters is reduced.  The initialization
is updated respectively.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>