cmd/compile: gofmt rewriteARM64.go

Change-Id: I7424257e496f8f40c9601b62335b64d641dcd3b5
Reviewed-on: https://go-review.googlesource.com/99996
Run-TryBot: Giovanni Bajo <rasky@develer.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

src/cmd/compile/internal/ssa/rewriteARM64.go

@@ -22057,4 +22057,4 @@ func rewriteBlockARM64(b *Block) bool {
 		}
 	}
 	return false
-}
+}
\ No newline at end of file