GekkoDisassembler: fix/improve disassembly for a few instructions

You need to brace the case like so:

```cpp
case 96:
{
    m_opcode = "ps_cmpo1";
    m_operands = "ps_cmpo1";
    m_opcode = StringFromFormat("%s", ps_cmpname[(inst >> 6) & 0x3]);

    int  i = (int)PPCGETCRD(inst);
     if (i != 0)
         m_operands += StringFromFormat("cr%c, ", '0' + i);
     m_operands += StringFromFormat("p%u, p%u", FA, FB);
    return;
}
```