[gn] port f445be9

Author: nico

llvm/utils/gn/secondary/compiler-rt/lib/builtins/BUILD.gn

@@ -473,6 +473,8 @@ static_library("builtins") {
     sources -= [ "fp_mode.c" ]
     sources += [
       "aarch64/fp_mode.c",
+      "aarch64/sme-abi-init.c",
+      "aarch64/sme-abi.S",
       "cpu_model.c",
     ]
     if (current_os == "mingw") {