[gn build] Port fef54d0

Author: llvmgnsyncbot

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

@@ -179,6 +179,8 @@ static_library("LLVMAMDGPUCodeGen") {
     "AMDGPUPromoteAlloca.cpp",
     "AMDGPUPromoteKernelArguments.cpp",
     "AMDGPURegBankCombiner.cpp",
+    "AMDGPURegBankLegalize.cpp",
+    "AMDGPURegBankSelect.cpp",
     "AMDGPURegisterBankInfo.cpp",
     "AMDGPURemoveIncompatibleFunctions.cpp",
     "AMDGPUReserveWWMRegs.cpp",