perf/x86/intel: Move BTS index to 47

The bit 48 in the PERF_GLOBAL_STATUS is used to indicate the overflow
status of the PERF_METRICS counters.

Move the BTS index to the bit 47.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-5-kan.liang@linux.intel.com

arch/x86/include/asm/perf_event.h

@@ -238,11 +238,11 @@ struct x86_pmu_capability {
 /*
  * We model BTS tracing as another fixed-mode PMC.
  *
- * We choose a value in the middle of the fixed event range, since lower
+ * We choose the value 47 for the fixed index of BTS, since lower
  * values are used by actual fixed events and higher values are used
  * to indicate other overflow conditions in the PERF_GLOBAL_STATUS msr.
  */
-#define INTEL_PMC_IDX_FIXED_BTS			(INTEL_PMC_IDX_FIXED + 16)
+#define INTEL_PMC_IDX_FIXED_BTS			(INTEL_PMC_IDX_FIXED + 15)
 
 #define GLOBAL_STATUS_COND_CHG			BIT_ULL(63)
 #define GLOBAL_STATUS_BUFFER_OVF_BIT		62