More displayPort_t, CANVAS as new feature, multi-display cycling

- Further touch-ups with displayPort_t handling.
- CANVAS is a FEATURE now.
- Device specific xxxCmsInit() are registered by device’s init, and
called by CMS upon entry to menu.
- Multiple display devices can be cycled by entering menu invocation
command while in menu.
- The menu invocation command is (was) changed to THR-Mid + YAW-Left +
Pitch-Full to avoid collision with MWOSD menu invocation command.
- More separation attempt.

src/main/fc/fc_msp.c

@@ -101,15 +101,6 @@
 #include "config/config_master.h"
 #include "config/feature.h"
 
-#ifdef USE_DPRINTF
-#include "common/printf.h"
-#define DPRINTF_SERIAL_PORT SERIAL_PORT_USART3
-extern serialPort_t *debugSerialPort;
-#define dprintf(x) if (debugSerialPort) printf x
-#else
-#define dprintf(x)
-#endif
-
 #ifdef USE_HARDWARE_REVISION_DETECTION
 #include "hardware_revision.h"
 #endif