Michael Maltese 4cd9a2ef1e DiscIO: make sure to initialize out args to ReadSwapped
Fixes warnings:

```
../Source/Core/DiscIO/VolumeGC.cpp: In member function 'virtual u8 DiscIO::CVolumeGC::GetDiscNumber() const':
../Source/Core/DiscIO/VolumeGC.cpp:178:10: error: 'disc_number' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   return disc_number;
          ^
../Source/Core/DiscIO/VolumeWiiCrypted.cpp: In member function 'virtual u8 DiscIO::CVolumeWiiCrypted::GetDiscNumber() const':
../Source/Core/DiscIO/VolumeWiiCrypted.cpp:258:10: error: 'disc_number' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   return disc_number;
          ^
../Source/Core/DiscIO/VolumeWiiCrypted.cpp: In member function 'virtual IOS::ES::TMDReader DiscIO::CVolumeWiiCrypted::GetTMD() const':
../Source/Core/DiscIO/VolumeWiiCrypted.cpp:123:20: error: 'tmd_address' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   tmd_address <<= 2;
                    ^
```
2017-03-25 13:50:23 -07:00
..
2017-03-22 20:35:00 -04:00
2017-03-08 01:24:18 -08:00