DiscIO: Prefix class member variables with "m_"

Source/Core/DiscIO/VolumeWad.h

@@ -39,7 +39,12 @@ public:
 
 private:
 	std::unique_ptr<IBlobReader> m_pReader;
-	u32 OpeningBnrOffset, hdr_size, cert_size, tick_size, tmd_size, data_size;
+	u32 m_opening_bnr_offset;
+	u32 m_hdr_size;
+	u32 m_cert_size;
+	u32 m_tick_size;
+	u32 m_tmd_size;
+	u32 m_data_size;
 	u8 m_Country;
 };