perf vendor events power9: Branch_prediction, instruction_stats, latency, lsu_rejects, memory, prefetch & translation metrics

Descriptions of metrics for POWER9 processors can be found in the
"POWER9 Performance Monitor Unit User’s Guide", which is currently
available on the "IBM Portal for OpenPOWER"
(https://www-355.ibm.com/systems/power/openpower/welcome.xhtml) at
https://www-355.ibm.com/systems/power/openpower/posting.xhtml?postingId=4948CDE1963C9BCA852582F800718190

This patch is for metric groups:
- branch_prediction
- instruction_stats_percent_per_ref
- latency
- lsu_rejects
- memory
- prefetch
- translation

Plus, some whitespace changes.
Signed-off-by: Paul Clarke <pc@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Carl Love <cel@us.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: linuxppc-dev@ozlabs.org
Link: http://lkml.kernel.org/r/20190209181429.23950-4-pc@us.ibm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>