I mean, that product "Freescale MQX RTOS 3.2.1" does not support runtime switch between host and device functionality. In developing phase, you have to decide whether you will use host or device.
If your question leads whether you could find or buy another version of USB stack, the answer is: ask EAI Inc., but for MCUs that Freescale has released MQX for, EAI Inc. doesn't have any next features; in other words Freescale's MQX does not lack any functionality or feature compared to EAI.