interconnect/axi: map from one address space to another

[mkuhn99]

When trying to connect to the PS axi gp slave to the main Bus of the LiteX SoC I came across the problem that the address space of the zybo PS and the address space/memory map of the Litex SoC are conflicting.
To solve this problem I added the connect_mapped function to the AXIInterface, which applies a function to the address signals before connecting the two interfaces together.

Such a function would, for example, add or subtract an offset.

[mkuhn99]

Here is a case where one would/could use this function.

[enjoy-digital]

Thanks @mkuhn99, this is indeed interesting and I understand the need. Please just give me some time to think about it.