sync/atomic: fix LoadInt32 on ARM R0 is clobbered after cas, while R1 preserves its value.
sync/atomic: fix LoadInt32 on ARM
R0 is clobbered after cas,
while R1 preserves its value.

R=golang-dev
CC=golang-dev
http://codereview.appspot.com/4782042

Committer: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go