[FIX] Rename mpx* ipcores to prl*

This fix is necessary because the ipcores will be configurable to be
multiplexed and demultiplexed.

Change-Id: Ie2e3b531befde39ff3114365bbd6648d9f2ee73b
[FEATURE] Enable Demux and Mux modes in parallel interface ipcores

- Refactor parallel master ip
- Add demux and mux mode to parallel master and slave

Change-Id: I9b8b0db515b507c4ecf4731d0b1d1a761377bfe4
[FIX] Fix parallel ipcore release script

Change-Id: I4c5c97c13524a0360462ae110b58e43dfb8197d3