tools/power turbostat: Denverton uses a 25 MHz crystal, not 19.2 MHz

This changes only the TSC frequency decoding line seen with --debug

old: TSC: 1382 MHz (19200000 Hz * 216 / 3 / 1000000)
new: TSC: 1800 MHz (25000000 Hz * 216 / 3 / 1000000)

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