Memcard: Fix ECC and spare bytes when converting cards to raw format

Masks the unused bit out of the second line parity byte and leaves the
remaining spare bytes erased (0xff) instead of zeroed.

pcsx2/SIO/Memcard/MemoryCardFile.cpp

@@ -78,7 +78,7 @@ static u32 CalculateECC(u8* buf)
 		}
 	}
 
-	return column_parity | (line_parity_0 << 8) | (line_parity_1 << 16);
+	return column_parity | ((line_parity_0 & 0x7F) << 8) | (line_parity_1 << 16);
 }
 
 static bool ConvertNoECCtoRAW(const char* file_in, const char* file_out)
@@ -109,8 +109,9 @@ static bool ConvertNoECCtoRAW(const char* file_in, const char* file_out)
 				return false;
 		}
 
-		u32 nullbytes = 0;
-		if (std::fwrite(&nullbytes, sizeof(nullbytes), 1, fout.get()) != 1)
+		// unwritten spare reads back erased
+		const u32 unused = 0xffffffff;
+		if (std::fwrite(&unused, sizeof(unused), 1, fout.get()) != 1)
 			return false;
 	}