Interrupt timer io updates

Created by: timsaxe

Hi folks,

I think I did this correctly. I created branch for core-v-mcu and core-v-mcu-soc. Confirmed that they correctly generate a bitstream and ran my minimal regression test (UART + memory). Let me know if I should be doing things differently. It has the revised interrupt, revised timer, more scalable I/O, and changes to make UDMA peripherals easier to add/delete.

Tried to keep the ASIC specific proprietary material as an overlay -- I test with that so I am not 100% sure that a build will work without it -- it should but not tested.

Tim