ft4222: move calls to libft4222.so to use dlopen

Makes the lib a runtime only dependency

Signed-off-by: Thomas Ingleby <thomas.ingleby@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

include/usb/ftdi_ft4222.h

@@ -28,12 +28,13 @@
 extern "C" {
 #endif
 
+#include <dlfcn.h>
 #include "mraa_internal.h"
 
 mraa_result_t mraa_ftdi_ft4222_init();
 mraa_result_t mraa_ftdi_ft4222_get_version(unsigned int* versionChip, unsigned int* versionLib);
 mraa_board_t* mraa_ftdi_ft4222();
-
+void *libft4222_lib;
 
 #ifdef __cplusplus
 }