Update the packbits kernel to use bitwise or
Update the packbits kernel to use bitwise or

cupy/cupy,chainer/chainer,chainer/chainer,okuta/chainer,keisuke-umezawa/chainer,tkerola/chainer,keisuke-umezawa/chainer,hvy/chainer,keisuke-umezawa/chainer,cupy/cupy,hvy/chainer,jnishi/chainer,jnishi/chainer,ktnyt/chainer,keisuke-umezawa/chainer,pfnet/chainer,okuta/chainer,hvy/chainer,anaruse/chainer,cupy/cupy,ktnyt/chainer,hvy/chainer,okuta/chainer,ktnyt/chainer,niboshi/chainer,niboshi/chainer,okuta/chainer,chainer/chainer,jnishi/chainer,wkentaro/chainer,kiyukuta/chainer,cupy/cupy,jnishi/chainer,kashif/chainer,chainer/chainer,wkentaro/chainer,delta2323/chainer,wkentaro/chainer,rezoo/chainer,wkentaro/chainer,niboshi/chainer,aonotas/chainer,niboshi/chainer,ktnyt/chainer,ronekko/chainer,ysekky/chainer