tools/power turbostat: add precision to --debug frequency output

Add a digit of precision to the --debug output for frequency range.
This is useful when BCLK is not an integer.

old:
6 * 83 = 500 MHz max efficiency frequency
26 * 83 = 2166 MHz base frequency

new:
6 * 83.3 = 499.8 MHz max efficiency frequency
26 * 83.3 = 2165.8 MHz base frequency

Signed-off-by: Len Brown <len.brown@intel.com>