ueventd: Ueventd changes the permission of sysfs files for max/min

cpufreq

The owner and permissions for the sysfs file
/sys/devices/system/cpu*/cpufreq/scaling_max/min_freq is changed.
This would allow the PowerHAL to change the max/min cpufreq even after
the associated CPU's are hotplugged out and back in.

Change-Id: Ibe0b4aaf3db555ed48e89a7fcd0c5fd3a18cf233
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>