Update docs in upsampling_2d according to new max_pooling_2d
Update docs in upsampling_2d according to new max_pooling_2d

hvy/chainer,ktnyt/chainer,jnishi/chainer,keisuke-umezawa/chainer,okuta/chainer,tkerola/chainer,ronekko/chainer,wkentaro/chainer,keisuke-umezawa/chainer,hvy/chainer,okuta/chainer,ktnyt/chainer,hvy/chainer,niboshi/chainer,keisuke-umezawa/chainer,jnishi/chainer,chainer/chainer,okuta/chainer,hvy/chainer,pfnet/chainer,ktnyt/chainer,rezoo/chainer,wkentaro/chainer,ktnyt/chainer,wkentaro/chainer,niboshi/chainer,chainer/chainer,jnishi/chainer,wkentaro/chainer,okuta/chainer,keisuke-umezawa/chainer,jnishi/chainer,chainer/chainer,niboshi/chainer,chainer/chainer,niboshi/chainer