Fix wrong size generated FB which uses for render-to-texture

This commit may need wider testing before merge as usual , it fixes some wrong size generated FB for some games which uses it as render-to-texture where correct FB size is necessary .

[Test build]
![ppssppwindows](https://f.cloud.github.com/assets/3000282/942360/7472d8ae-01a6-11e3-9bcd-fda0d40d9ac2.jpg)

1. Sol Trigger
-Before
![screen00005](https://f.cloud.github.com/assets/3000282/942319/a4fa4428-019f-11e3-8a25-b78872e721f0.jpg)
-After
![screen00004](https://f.cloud.github.com/assets/3000282/942320/ab953522-019f-11e3-8c88-16f0ac09bd92.jpg)

2. Kurohyou 2
-Before
![screen00001](https://f.cloud.github.com/assets/3000282/942321/b2490b64-019f-11e3-9918-ea35cf99635c.jpg)
After
![screen00000](https://f.cloud.github.com/assets/3000282/942322/ba051e10-019f-11e3-88b5-24f5de2c5f38.jpg)

3. Evangelion Jo
-Before
![screen00002](https://f.cloud.github.com/assets/3000282/942323/d46a6012-019f-11e3-8ff6-0dc57d0d7fb8.jpg)
-After
![screen00003](https://f.cloud.github.com/assets/3000282/942324/d923e9d4-019f-11e3-8d15-c8c1ca8bc960.jpg)