cpupower: Correct macro name for CPB caps flag

The name is Core Performance Boost (CPB) for the cpuid flag. Correct
cpuid caps flag to use this name (instead of CBP).

Signed-off-by: Robert Richter <rrichter@amd.com>
Signed-off-by: Nathan Fontenot <nathan.fontenot@amd.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>