Description of problem:

mpstat shows one extra cpu

Version-Release number of selected component (if applicable):

sysstat-8.0.4-3.fc9.x86_64

How reproducible:

Very (if /sys is mounted)

Steps to Reproduce:
1. mpstat -P ALL
  
Actual results:

output show one extra cpu (quad core sample output):
Linux 2.6.25-0.204.rc8.git4.fc9.x86_64 (localhost.localdomain)  04/16/2008

02:07:41 PM  CPU   %user   %nice    %sys %iowait    %irq   %soft  %steal   %idle
   intr/s
02:07:41 PM  all    0.36    0.03    0.14    0.03    0.00    0.00    0.00   99.44
     6.23
02:07:41 PM    0    0.07    0.01    0.03    0.01    0.00    0.00    0.00   99.88
     0.44
02:07:41 PM    1    0.97    0.02    0.30    0.02    0.00    0.00    0.00   98.69
     0.60
02:07:41 PM    2    0.20    0.01    0.10    0.03    0.00    0.00    0.00   99.65
     2.02
02:07:41 PM    3    0.20    0.06    0.13    0.05    0.00    0.00    0.00   99.56
     3.17
02:07:41 PM    4    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00
     0.00

Note the seemingly unused cpu4.

Expected results:
stats for all plus cpu0-3 on the example quadcore system

Additional info:

This is a result of get_sys_cpu_nr making the assumption that any dir:
/sys/devices/system/cpu/cpu*/ represents a cpu thread.  However there is at
least /sys/devices/system/cpu/cpuidle/ which makes get_sys_cpu_nr return one too
many cpus.  Patch below is tested and works fine here.