Add a missing module sceSha256 found in Tantei Jinguji Saburo no functional

```
30:34:745 HLE\sceKernelModule.cpp:1078 D[LOAD]: Importing Module sceSha256, stubs at 0887527c
30:34:745 HLE\sceKernelModule.cpp:303 D[LOAD]: Importing [UNK: 0x318a350c] : 0887527c
30:34:745 HLE\sceKernelModule.cpp:680 I[LOAD]: Function (sceSha256,318a350c) unresolved, storing for later resolving
```
Fixed saving problem in Tantei Jinguji Saburo.

Before was not able to creat a savefile and even put the savefile to save folder,it hanged on loading.
![01](https://cloud.githubusercontent.com/assets/3481559/5300088/ee4d1ebe-7c07-11e4-8fb6-21aab433c64d.png)

I google sceSha256Digest and find this
```
 int sceSha256Digest(const u8 *plain, u32 len, u8 *digest)
```
 in http://pastie.org/pastes/585485 ,Is that useful.