Fix malformed screen rendering in Kurohyou 2 

Since the FBO size generated should be much more correct now and the original enlarge framebuffer may no longer needed (and indeed causes continuous enlarge framebuffer in some games)

Before
![screen00012](https://f.cloud.github.com/assets/3000282/830049/b7b0a51a-f125-11e2-803a-3e79d5cc41eb.jpg)

After
![screen00011](https://f.cloud.github.com/assets/3000282/830050/bb0cf42a-f125-11e2-9eac-5da02cfe862b.jpg)