[AMDGPU][NFC] Add GFX numbers to DefaultComponent feature (#77894)

Author: mariusz-sikora-at-amd

llvm/lib/Target/AMDGPU/AMDGPU.td

@@ -722,13 +722,13 @@ def FeatureFlatAtomicFaddF32Inst
 def FeatureDefaultComponentZero : SubtargetFeature<"default-component-zero",
   "HasDefaultComponentZero",
   "true",
-  "BUFFER/IMAGE store instructions set unspecified components to zero"
+  "BUFFER/IMAGE store instructions set unspecified components to zero (before GFX12)"
 >;
 
 def FeatureDefaultComponentBroadcast : SubtargetFeature<"default-component-broadcast",
   "HasDefaultComponentBroadcast",
   "true",
-  "BUFFER/IMAGE store instructions set unspecified components to x component"
+  "BUFFER/IMAGE store instructions set unspecified components to x component (GFX12)"
 >;
 
 def FeatureSupportsSRAMECC : SubtargetFeature<"sramecc-support",