Fix ploaddup and lin-spaced with AltiVec.
Fix ploaddup and lin-spaced with AltiVec.

rotorliu/eigen,mjbshaw/Eigen,rotorliu/eigen,mjbshaw/Eigen,rotorliu/eigen,madlib/eigen_backup,rotorliu/eigen,mjbshaw/Eigen,mjbshaw/Eigen,madlib/eigen_backup,madlib/eigen_backup,madlib/eigen_backup