skpbench: fix typo in 6P bash script

tools/skpbench/_hardware_nexus_6p.py

 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from _hardware import HardwareException, Expectation
 from _hardware_android import HardwareAndroid
 
 CPU_CLOCK_RATE = 1728000
 GPU_CLOCK_RATE = 510000000
@@ skipping 88 matching lines @@
 
     # turn the disabled cores back on.
     self._adb.shell('''\
       for N in 7 3 2 1 0; do
         echo 1 > /sys/devices/system/cpu/cpu$N/online
       done''')
 
     # unlock the 3 enabled big cores.
     self._adb.shell('''\
       for N in 6 5 4; do
-        echo 633600 > /sys/devices/system/cpu/cpu4/cpufreq/scaling_min_freq
-        echo 1958400 > /sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq
+        echo 633600 > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_min_freq
+        echo 1958400 > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_max_freq
         echo 0 > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_setspeed
         echo interactive > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_governor
       done''')
 
     self._adb.shell('''\
       start mpdecision
       start perfd
       start thermald
       start thermal-engine''')
 
@@ skipping 25 matching lines @@
                    name='ddr clock rate', sleeptime=10)] + \
       [Expectation(int, exact_value=CPU_CLOCK_RATE, name='cpu_%i clock rate' %i)
        for i in range(4, 7)]
 
     Expectation.check_all(expectations, result)
 
   def sleep(self, sleeptime):
     self._unlock_clocks()
     HardwareAndroid.sleep(self, sleeptime)
     self._lock_clocks()