[AMDGPU] Add v2bf16 for opsel immediate folding (#82435)

This was previously enabled since v2bf16 was represented by v2f16. As of
now it is NFC since we only have dot instructions which could use it,
but currently folding is guarded by the hasDOTOpSelHazard().

Author: rampitec

llvm/lib/Target/AMDGPU/SIFoldOperands.cpp

@@ -219,8 +219,10 @@ bool SIFoldOperands::canUseImmWithOpSel(FoldCandidate &Fold) const {
   default:
     return false;
   case AMDGPU::OPERAND_REG_IMM_V2FP16:
+  case AMDGPU::OPERAND_REG_IMM_V2BF16:
   case AMDGPU::OPERAND_REG_IMM_V2INT16:
   case AMDGPU::OPERAND_REG_INLINE_C_V2FP16:
+  case AMDGPU::OPERAND_REG_INLINE_C_V2BF16:
   case AMDGPU::OPERAND_REG_INLINE_C_V2INT16:
     break;
   }