We have ALIGN_{8,16,PAGE} and FLOOR_PAGE macros (where PAGE is defined as
4k) which were imported from the ppc sim. But no other sim utilizes these
and hardcoding the sizes in the name is a bit limiting.
Let's delete these and import the two general macros that gdb uses:
align_up(addr, bytes)
align_down(addr, bytes)
This in turn allows us to cut over the Blackfin code immediately.