acpi-cpufreq: Use cpufreq_freq_attr_rw to define the cpb attribute
acpi-cpufreq: Use cpufreq_freq_attr_rw to define the cpb attribute

Standardise the defintion of the cpb (Core Performance Boost)
attribute in the acpi-cpufreq driver via the cpufreq_freq_attr_rw
macro.

[rjw: Subject and changelog]
Signed-off-by: Lan Tianyu <4221d0916eb5c472a0ab46f0107445bbb3e8a589@intel.com>
Signed-off-by: Rafael J. Wysocki <27ffc44a8ec6a212fba98cfc3246c6ce8ab131e0@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs