[AMDGPU][Disassembler] Use target feature for .amdhsa_reserve_xnack_mask instead of hard code zero

There is no test change at this moment because we don't have a target that has this feature by default yet.

Author: shiltian

llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp

@@ -2303,7 +2303,12 @@ Expected<bool> AMDGPUDisassembler::decodeCOMPUTE_PGM_RSRC1(
   KdStream << Indent << ".amdhsa_reserve_vcc " << 0 << '\n';
   if (!hasArchitectedFlatScratch())
     KdStream << Indent << ".amdhsa_reserve_flat_scratch " << 0 << '\n';
-  KdStream << Indent << ".amdhsa_reserve_xnack_mask " << 0 << '\n';
+  bool ReservedXnackMask = STI.hasFeature(AMDGPU::FeatureXNACK);
+#ifndef NDEBUG
+  assert(!ReservedXnackMask || STI.hasFeature(AMDGPU::FeatureSupportsXNACK));
+#endif
+  KdStream << Indent << ".amdhsa_reserve_xnack_mask " << ReservedXnackMask
+           << '\n';
   KdStream << Indent << ".amdhsa_next_free_sgpr " << NextFreeSGPR << "\n";
 
   CHECK_RESERVED_BITS(COMPUTE_PGM_RSRC1_PRIORITY);