ToPackets incorrectly parses MIDIPacket

According to MIDIServices.h `MIDIPacket` comment:
```
... the alignment requirements of MIDIPacket may differ between CPU architectures. On Intel and PowerPC, MIDIPacket is unaligned. On ARM, MIDIPacket must be 4-byte aligned.
```

`MidiPort.ToPackets` should correctly handle such cases.