ACPI: CPPC: Amend documentation in the comments

Currently it's too hard to read the _CPC structure as it's commented.
Reshuffle indentation and style to make it readable.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>