The memory mapped AXI interfaces for the AXI-DMAC are uni-directional.
Which means they are either write-only or read-only. Unfortunately the
Altera tools can't handle this, so we had to add dummy signals for the
other direction.
The Xilinx tools on the other hand handle uni-directional AXI interfaces
and in fact IPI can do a better job and use less resources when creating
the AXI interconnects when it knows that the interface is uni-directional.
So always disable the dummy ports for the IPI package.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>