syscall: apply comment from Mikioh
syscall: apply comment from Mikioh

This comment was suggested in CL 6456045
but never got applied.

R=mikioh, mikioh.mikioh
CC=golang-dev
http://codereview.appspot.com/6447056

firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang,wesolows/golang,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang,wesolows/golang-old,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,wesolows/golang,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang-old