Remove xnack_mask for all gfx10+ except gfx10.1

The XNACK feature and the associated xnack_mask register were removed
from all gfx10+ architectures starting with gfx10.3. gfx10.1 still
supports XNACK, but only 32bit wide.

Change-Id: Ibe35f1070e315df3821d28a2b893c0c071f0b291

src/architecture.cpp

@@ -4283,11 +4283,16 @@ gfx10_architecture_t::gfx10_architecture_t (elf_amdgpu_machine_t e_machine,
                { return register_class.name () == "system"; });
   dbgapi_assert (system_registers != nullptr);
 
-  system_registers->add_registers (amdgpu_regnum_t::xnack_mask_32,
-                                   amdgpu_regnum_t::xnack_mask_32);
   system_registers->remove_registers (amdgpu_regnum_t::xnack_mask_64,
                                       amdgpu_regnum_t::xnack_mask_64);
 
+  /* gfx10.1 still supports xnack_mask, but only 32bit wide.  */
+  if (e_machine == EF_AMDGPU_MACH_AMDGCN_GFX1010
+      || e_machine == EF_AMDGPU_MACH_AMDGCN_GFX1011
+      || e_machine == EF_AMDGPU_MACH_AMDGCN_GFX1012)
+    system_registers->add_registers (amdgpu_regnum_t::xnack_mask_32,
+                                     amdgpu_regnum_t::xnack_mask_32);
+
   /* General registers: [s103-s105, {vector}_32, exec_32, vcc_32]  */
   register_class_t *general_registers
     = find_if ([] (const register_class_t &register_class)