[CPUFREQ] powernow-k8: Avoid Pstate MSR accesses on systems supporting CPB

Due to CPB we can't directly map SW Pstates to Pstate MSRs. Get rid of
the paranoia check. (assuming that the ACPI Pstate information is
correct.)

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index bce576d..e0329f9 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -926,23 +926,24 @@
 			invalidate_entry(powernow_table, i);
 			continue;
 		}
-		rdmsr(MSR_PSTATE_DEF_BASE + index, lo, hi);
-		if (!(hi & HW_PSTATE_VALID_MASK)) {
-			pr_debug("invalid pstate %d, ignoring\n", index);
-			invalidate_entry(powernow_table, i);
-			continue;
-		}
-
-		powernow_table[i].index = index;
-
 		/* Frequency may be rounded for these */
 		if ((boot_cpu_data.x86 == 0x10 && boot_cpu_data.x86_model < 10)
 				 || boot_cpu_data.x86 == 0x11) {
+
+			rdmsr(MSR_PSTATE_DEF_BASE + index, lo, hi);
+			if (!(hi & HW_PSTATE_VALID_MASK)) {
+				pr_debug("invalid pstate %d, ignoring\n", index);
+				invalidate_entry(powernow_table, i);
+				continue;
+			}
+
 			powernow_table[i].frequency =
 				freq_from_fid_did(lo & 0x3f, (lo >> 6) & 7);
 		} else
 			powernow_table[i].frequency =
 				data->acpi_data.states[i].core_frequency * 1000;
+
+		powernow_table[i].index = index;
 	}
 	return 0;
 }