pcsx2: use int instead of uint on file reader

Fix a crash when offset was negative. Offet becomes bigger than my input file.

pcsx2/AsyncFileReader.h

@@ -25,11 +25,11 @@
 class AsyncFileReader
 {
 protected:
-	AsyncFileReader(void) {m_dataoffset=0;}
+	AsyncFileReader() : m_dataoffset(0) {}
 
 	wxString m_filename;
 
-	uint m_dataoffset;
+	int m_dataoffset;
 	uint m_blocksize;
 
 public:
@@ -48,7 +48,7 @@ public:
 	virtual uint GetBlockCount(void) const=0;
 
 	virtual void SetBlockSize(uint bytes) {}
-	virtual void SetDataOffset(uint bytes) {}
+	virtual void SetDataOffset(int bytes) {}
 
 	uint GetBlockSize() const { return m_blocksize; }
 
@@ -92,7 +92,7 @@ public:
 	virtual uint GetBlockCount(void) const;
 
 	virtual void SetBlockSize(uint bytes) { m_blocksize = bytes; }
-	virtual void SetDataOffset(uint bytes) { m_dataoffset = bytes; }
+	virtual void SetDataOffset(int bytes) { m_dataoffset = bytes; }
 };
 
 // Factory - creates an AsyncFileReader derived instance which can read a compressed file

pcsx2/CDVD/CompressedFileReader.cpp

@@ -225,7 +225,7 @@ public:
 	};
 
 	virtual void SetBlockSize(uint bytes) { m_blocksize = bytes; }
-	virtual void SetDataOffset(uint bytes) { m_dataoffset = bytes; }
+	virtual void SetDataOffset(int bytes) { m_dataoffset = bytes; }
 private:
 	class Czstate {
 	public:

pcsx2/Linux/LnxFlatFileReader.cpp

@@ -49,7 +49,7 @@ int FlatFileReader::ReadSync(void* pBuffer, uint sector, uint count)
 void FlatFileReader::BeginRead(void* pBuffer, uint sector, uint count)
 {
 	u64 offset;
-	offset = sector * (u64)m_blocksize + m_dataoffset;
+	offset = sector * (s64)m_blocksize + m_dataoffset;
 
 	u32 bytesToRead = count * m_blocksize;