Rename "rdt" to "rdt_a"

The final merged patch in Linux 4.10,
4ab1586488cb56ed8728e54c4157cc38646874d9 ("x86/cpufeature: Add RDT CPUID
feature bits") named this feature "rdt_a". Earlier patch sets had named
this "rdt".

PiperOrigin-RevId: 234680481
Change-Id: I0cc968201ec9a2825701405e207994a7331322b7

pkg/cpuid/cpuid.go

@@ -338,7 +338,7 @@ var x86FeatureStrings = map[Feature]string{
 	X86FeatureRTM:        "rtm",
 	X86FeatureCQM:        "cqm",
 	X86FeatureMPX:        "mpx",
-	X86FeatureRDT:        "rdt",
+	X86FeatureRDT:        "rdt_a",
 	X86FeatureAVX512F:    "avx512f",
 	X86FeatureAVX512DQ:   "avx512dq",
 	X86FeatureRDSEED:     "rdseed",

pkg/cpuid/cpuid_parse_test.go

@@ -101,6 +101,11 @@ func TestHostFeatureFlags(t *testing.T) {
 			// SDBG only exposed in
 			// b1c599b8ff80ea79b9f8277a3f9f36a7b0cfedce (4.3).
 			continue
+		// Block 2.
+		case f == X86FeatureRDT && (major < 4 || major == 4 && minor < 10):
+			// RDT only exposed in
+			// 4ab1586488cb56ed8728e54c4157cc38646874d9 (4.10).
+			continue
 		// Block 3.
 		case f == X86FeatureAVX512VBMI && (major < 4 || major == 4 && minor < 10):
 			// AVX512VBMI only exposed in
@@ -111,8 +116,8 @@ func TestHostFeatureFlags(t *testing.T) {
 			// 3522c2a6a4f341058b8291326a945e2a2d2aaf55 (4.15).
 			continue
 		case f == X86FeaturePKU && (major < 4 || major == 4 && minor < 9):
-			// PKU only exposed in dfb4a70f20c5b3880da56ee4c9484bdb4e8f1e65
-			// (4.9).
+			// PKU only exposed in
+			// dfb4a70f20c5b3880da56ee4c9484bdb4e8f1e65 (4.9).
 			continue
 		// Block 4.
 		case f == X86FeatureXSAVES && (major < 4 || major == 4 && minor < 8):