oprofile, s390: Add support for hardware based sampling on System z processors

This adds support for hardware based sampling on System z processors
(models z10 and up).

System z's hardware sampling is described in detail in:

   SA23-2260-01 "The Load-Program-Parameter and CPU-Measurement Facilities"

The patch introduces

 - support for System z's hardware sampler in OProfile's kernel module
 - it adds functions that control all hardware sampling related
   operations as:
   - checking if hardware sampling feature is available, i.e.: on
     System z models z10 and up, in LPAR mode only, and authorised
     during LPAR activation
   - allocating memory for the hardware sampling feature
   - starting/stopping hardware sampling

All functions required to start and stop hardware sampling have to be
invoked by the oprofile kernel module as provided by the other patches
of this patch set.

In case hardware based sampling cannot be setup standard timer based
sampling is used by OProfile.

Applied with following changes:
* enable compilation in Makefile

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Maran Pakkirisamy <maranp@linux.vnet.ibm.com>
Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>