[gn build] Port 87503fa

Author: llvmgnsyncbot

llvm/utils/gn/secondary/llvm/lib/Target/AMDGPU/BUILD.gn

@@ -179,7 +179,6 @@ static_library("LLVMAMDGPUCodeGen") {
     "AMDGPUPromoteAlloca.cpp",
     "AMDGPUPromoteKernelArguments.cpp",
     "AMDGPURegBankCombiner.cpp",
-    "AMDGPURegBankSelect.cpp",
     "AMDGPURegisterBankInfo.cpp",
     "AMDGPURemoveIncompatibleFunctions.cpp",
     "AMDGPUReserveWWMRegs.cpp",