Add basic char device mechanism
Begin the FIQ<-> char dev integration

This won't work because the timer variable is copied by set_fiq_handler.
We need to pass a pointer.
Add mmap
Add a dumb fiq client
Add allocation code, mmap test code, ioctls

Also switch back to regular IRQs to validate all the mapping/ioctl stuff
before going forward more easily.

The protocol is not yet completely implemented.
Update the dumb client to use ioctls to start the FIQ