Async FIFO master / slave
I'm not familiar with the specifics of the devices you referenced, but in a general async FIFO there is a "pushing" side and a "popping" side.

The side which pushes into the FIFO is usually called master, and the side that pops from it is a target.

I don't understand why do you have difficulties in identifying the master without clock - the side which initiates the transaction is a master. I hope I didn't misunderstand your question...