Linux: Added config and stubs to compile I2C device for Linux

Not yet functional. Full implementation will provide an IOCTL interface to
do bi-directional transfer. will model the interface after Linux.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/drivers/ms5611/ms5611_linux.cpp

@@ -890,6 +890,7 @@ start_bus(struct ms5611_bus_option &bus)
 	if (bus.dev != nullptr && OK != bus.dev->init()) {
 		delete bus.dev;
 		bus.dev = NULL;
+		warnx("bus init failed %p", bus.dev);
 		return false;
 	}