x86: msr-index.h: define HWP.EPP values

The Hardware Performance State request MSR has a field
to express the "Energy Performance Preference" (HWP.EPP).

Decode that field so the definition may be shared by
by the intel_pstate driver and any utilities that
decode the same register.
Signed-off-by: NLen Brown <len.brown@intel.com>

arch/x86/include/asm/msr-index.h

@@ -239,6 +239,10 @@
 #define HWP_MAX_PERF(x) 		((x & 0xff) << 8)
 #define HWP_DESIRED_PERF(x)		((x & 0xff) << 16)
 #define HWP_ENERGY_PERF_PREFERENCE(x)	((x & 0xff) << 24)
+#define HWP_EPP_PERFORMANCE		0x00
+#define HWP_EPP_BALANCE_PERFORMANCE	0x80
+#define HWP_EPP_BALANCE_POWERSAVE	0xC0
+#define HWP_EPP_POWERSAVE		0xFF
 #define HWP_ACTIVITY_WINDOW(x)		((x & 0xff3) << 32)
 #define HWP_PACKAGE_CONTROL(x)		((x & 0x1) << 42)