The path to get cpu frequency is not correct in Android 7.0 or newer

[cuihao19931030]

ncnn/src/cpu.cpp

Line 225 in 2f16642

sprintf(path, "/sys/devices/system/cpu/cpufreq/stats/cpu%d/time_in_state", cpuid);

sprintf(path, "/sys/devices/system/cpu/cpufreq/stats/cpu%d/time_in_state", cpuid);
The path to get cpu frequency is not correct in my phone and arm development board which run Android 7.0
In the condition I said, the path is " /sys/devices/system/cpu/cpu%d/cpufreq/stats/time_in_state" .