[llvm] [AMDGPU][True16][MC] fix fmac_f16_t16 vop3 format (PR #135464)

[Matt Arsenault via llvm-commits]

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@@ -624,7 +624,9 @@ bool isMAC(unsigned Opc) {
          Opc == AMDGPU::V_FMAC_LEGACY_F32_e64_gfx10 ||
          Opc == AMDGPU::V_FMAC_DX9_ZERO_F32_e64_gfx11 ||
          Opc == AMDGPU::V_FMAC_F16_e64_gfx10 ||
+         Opc == AMDGPU::V_FMAC_F16_t16_e64_gfx11 ||
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arsenm wrote:

Is this function doing anything more than has tied operand? This should be moved to something on the instruction definition 

https://github.com/llvm/llvm-project/pull/135464