Convert iomux to use an UCoreClock

include/ucore/iomux.h

@@ -41,6 +41,13 @@ struct IOMuxFD {
  */
 struct IOMux *iomux_create(enum IOMUX_TYPE type);
 
+/** Creates a new IOMux with a user supplied clock
+ *
+ * The supplied clock is used for the UCTimers associated
+ * with the mux.
+ */
+struct IOMux *iomux_create_ex(enum IOMUX_TYPE type, struct UCoreClock *uclock);
+
 /** Deletes the IOMux and frees its resources.
  * Can not be called from within a callback */
 void iomux_delete(struct IOMux *mux);