Parts of a 'perf kvm stat' code make sense only for x86.

Let's move this code into the arch/x86/kvm-stat.c file and add
util/kvm-stat.h for generic structure definitions.

Add a global array 'kvm_reg_events_ops' for accessing the arch-specific
'kvm_events_ops' from generic code.

Since the several global arrays (i.e. 'kvm_events_tp') have been moved
to arch/*, we can not know their sizes and use them directly in
builtin-kvm.c. This patch fixes that problem by adding trimming NULL
element to each array and changing the behavior of their handlers in
generic code.
Reviewed-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1404397747-20939-3-git-send-email-yarygin@linux.vnet.ibm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>