Fix malformed screen rendering in Kurohyou_2_Ryu_ga_Gotoku_Ashura_Hen

Since the FBO size generated should be correct all the time and the original enlarge framebuffer size may no longer need (and indeed cause 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)