gRPC migration update

Change-Id: Icdd1a824948fa994cd36bd121c962f5ecf74e3cf
diff --git a/vendor/golang.org/x/sys/unix/asm_linux_ppc64x.s b/vendor/golang.org/x/sys/unix/asm_linux_ppc64x.s
index 88f7125..19d4989 100644
--- a/vendor/golang.org/x/sys/unix/asm_linux_ppc64x.s
+++ b/vendor/golang.org/x/sys/unix/asm_linux_ppc64x.s
@@ -2,9 +2,10 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build linux && (ppc64 || ppc64le) && gc
 // +build linux
 // +build ppc64 ppc64le
-// +build !gccgo
+// +build gc
 
 #include "textflag.h"