Add const keyword to the demo function parameters where possible.

Demos/Device/ClassDriver/MassStorage/MassStorage.c

Demos/Device/ClassDriver/MassStorage/MassStorage.h

...ice/ClassDriver/MassStorageKeyboard/MassStorageKeyboard.c

...ice/ClassDriver/MassStorageKeyboard/MassStorageKeyboard.h

Demos/Device/Incomplete/Sideshow/Lib/SideshowCommands.c

Demos/Device/Incomplete/Sideshow/Lib/SideshowCommands.h

Demos/Device/Incomplete/Sideshow/Lib/SideshowCommon.c

Demos/Device/Incomplete/Sideshow/Lib/SideshowCommon.h

Demos/Device/Incomplete/Sideshow/Lib/SideshowContent.c

Demos/Device/Incomplete/Sideshow/Lib/SideshowContent.h

Demos/Host/Incomplete/BluetoothHost/BluetoothHost.c

...s/Host/Incomplete/BluetoothHost/Lib/BluetoothACLPackets.c

...s/Host/Incomplete/BluetoothHost/Lib/BluetoothACLPackets.h

.../Host/Incomplete/BluetoothHost/Lib/BluetoothHCICommands.c

.../Host/Incomplete/BluetoothHost/Lib/BluetoothHCICommands.h

Demos/Host/Incomplete/BluetoothHost/Lib/BluetoothStack.c

Demos/Host/Incomplete/BluetoothHost/Lib/BluetoothStack.h

...t/Incomplete/BluetoothHost/Lib/ServiceDiscoveryProtocol.c

Demos/Host/LowLevel/KeyboardHostWithParser/HIDReport.h

Demos/Host/LowLevel/PrinterHost/Lib/PrinterCommands.c