[gn build] Port a6065f0

Author: llvmgnsyncbot

llvm/utils/gn/secondary/llvm/lib/Target/AArch64/BUILD.gn

@@ -109,6 +109,7 @@ static_library("LLVMAArch64CodeGen") {
     "AArch64A53Fix835769.cpp",
     "AArch64A57FPLoadBalancing.cpp",
     "AArch64AdvSIMDScalarPass.cpp",
+    "AArch64Arm64ECCallLowering.cpp",
     "AArch64AsmPrinter.cpp",
     "AArch64BranchTargets.cpp",
     "AArch64CallingConvention.cpp",