HW:CPU debug registers

The various CPU cores export entries in the ADT that hint at the existence of debug registers. The string "coresight" appears, and coresight register files are unlocked by writing 0xc5acce55 to offset 0xfb0, which is also what the Corellium CPU start code does. The lock status register is at 0x210030fb4 for CPU0.

CPU0's PC can be read at 0x210040090 (the usual offsets apply to the other cores), but the other registers don't appear to be making any obvious appearances.