Use of 15 vs. 16 entries in the binned memories

[aryd]

We have changed in the emulation (for the fw_synch_210613 tag) the number of stubs that are written to the binned memories to be maximum of 15. This addressed a problem in the ME when we had 16 stubs. I (aryd) was confused about what we could do in the HLS code - 16 should indeed be possible, we have 5 bits for the counter in the standard config and 4 bits + 1 but for empty/non-empty in the combined modules configuration. This should be sufficient to make this work. But for now we changed the VMR to produce at most 15 stubs. This should be fixed at some point, but not the highest priority at this point so we created this issue not to forget about this.