cpupower: remove stringop-truncation waring

The strncpy doesn't null terminate the string because the size is too
short by one byte.

parse.c: In function ‘prepare_default_config’:
parse.c:148:2: warning: ‘strncpy’ output truncated before terminating
    nul copying 8 bytes from a string of the same length
    [-Wstringop-truncation]
  strncpy(config->governor, "ondemand", 8);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The normal method of passing the length of the destination buffer works
correctly here.

Fixes: 7fe2f639 ("cpupowerutils - cpufrequtils extended with quite some features")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>