Rewrite cpudep_ap_bootstrap(). We now enable L3, L2, L1D and L1I

Rewrite cpudep_ap_bootstrap(). We now enable L3, L2, L1D and L1I
caches if not yet enabed. This is required for coherency and
atomic operations to work, not to mention performance. We use the
L2 and L3 cache settings of the BSP to configure the APs caches.
Can't be bad.

Program NAP and not DOZE. DOZE is present only on earlier CPUs
and the bit is reserved on the MPC7441 & MPC7451. NAP will do
bus snooping to keep caches coherent.

Program the PIR with the cpuid. This may not be necessary...