s390/pai_crypto: Add PAI crypto characteristics table for parameters

s390/pai_crypto: Add PAI crypto characteristics table for parameters

Create and add a PMU characteristics table to store the parameters
of the PAI crypto PMU. This table contains PMU details such as
 - number of available counters
 - name of these counters to export to /sysfs
 - Size of the memory mapped counter area
 - base number of first counter
 - etc

Also define a PMU specific initialization function to be called when
a PAI PMU feature is supported. At device driver initialization
test these features and if available use instruction qpaci to
retrieve the number of available counters. Also export these counter
names to /sysfs and register this PMU.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Jan Polensky <japo@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>