x86/cpu: Add advanced power management bits

Bit 11 of CPUID 8000_0007 edx is processor feedback interface.
Bit 12 of CPUID 8000_0007 edx is accumulated power.

Print proper names in proc/cpuinfo
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Cc: Tony Li <tony.li@amd.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Sherry Hurwitz <sherry.hurwitz@amd.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: "Len Brown" <lenb@kernel.org>
Link: http://lkml.kernel.org/r/1458871720-3209-1-git-send-email-ray.huang@amd.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/cpu/powerflags.c

@@ -18,4 +18,6 @@ const char *const x86_power_flags[32] = {
 	"",	/* tsc invariant mapped to constant_tsc */
 	"cpb",  /* core performance boost */
 	"eff_freq_ro", /* Readonly aperf/mperf */
+	"proc_feedback", /* processor feedback interface */
+	"acc_power", /* accumulated power mechanism */
 };