[AMDGPU][NFC] Fix missing size in comment

Author: perlfu

llvm/lib/Target/AMDGPU/SIRegisterInfo.h

@@ -41,7 +41,7 @@ class SIRegisterInfo final : public AMDGPUGenRegisterInfo {
   static std::array<std::vector<int16_t>, 16> RegSplitParts;
 
   // Table representing sub reg of given width and offset.
-  // First index is subreg size: 32, 64, 96, 128, 160, 192, 256, 512.
+  // First index is subreg size: 32, 64, 96, 128, 160, 192, 224, 256, 512.
   // Second index is 32 different dword offsets.
   static std::array<std::array<uint16_t, 32>, 9> SubRegFromChannelTable;