Print the correct bitmask for the running Book-E CPU

All the Book-E world is no longer e500v{1,2}. e500mc the 64-bit derivatives do
not use the DOZE/NAP bits with MSR[WE], instead using the `wait' instruction to
wait for interrupts, and SoC plane controls (via CCSR) for power management.

MFC after: 1 week