cmd/compile/internal/ppc64: improve naming for ginsnop2

This is a follow up from a review comment at the end of the last
Go release, to provide a more meaningful name for ginsnop2.

Updates #30475

Change-Id: Ice9efd763bf2204a9e8c55ae230d3e8a80210108
Reviewed-on: https://go-review.googlesource.com/c/go/+/174757
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

src/cmd/compile/internal/ppc64/galign.go

@@ -21,7 +21,7 @@ func Init(arch *gc.Arch) {
 	arch.ZeroRange = zerorange
 	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
-	arch.Ginsnopdefer = ginsnop2
+	arch.Ginsnopdefer = ginsnopdefer
 
 	arch.SSAMarkMoves = ssaMarkMoves
 	arch.SSAGenValue = ssaGenValue

src/cmd/compile/internal/ppc64/ggen.go

@@ -67,8 +67,9 @@ func ginsnop(pp *gc.Progs) *obj.Prog {
 	return p
 }
 
-func ginsnop2(pp *gc.Progs) *obj.Prog {
-	// PPC64 is unusual because TWO nops are required
+func ginsnopdefer(pp *gc.Progs) *obj.Prog {
+	// On PPC64 two nops are required in the defer case.
+	//
 	// (see gc/cgen.go, gc/plive.go -- copy of comment below)
 	//
 	// On ppc64, when compiling Go into position