remove reference to `lq` not being useful because SVP64 replaces it...
it *is* useful...because it's a 128-bit atomic op. SVP64 doesn't
convert 64-bit ops into 128-bit atomic ops so therefore can't be
used to replace lq.
Revert "Revert "Revert """"
This reverts commit
cf119cf4cf39ef8ffff5bbaada1a362dfa947dcf.