USBMIDI::write: avoid pointless copy

Author: thirtythreeforty

drivers/usb/include/usb/USBMIDI.h

@@ -118,7 +118,7 @@ class USBMIDI: public USBDevice {
      * @param m The MIDIMessage to send
      * @return true if the message was sent, false otherwise
      */
-    bool write(MIDIMessage m);
+    bool write(const MIDIMessage& m);
 
     /**
      * Check if a message can be read

drivers/usb/source/USBMIDI.cpp

@@ -78,7 +78,7 @@ void USBMIDI::wait_ready()
 }
 
 // write plain MIDIMessage that will be converted to USBMidi event packet
-bool USBMIDI::write(MIDIMessage m)
+bool USBMIDI::write(const MIDIMessage& m)
 {
     _write_mutex.lock();