o Properly set ksym_start & ksym_end when options DDB is set.
Include opt_ddb.h for that. Now you can actually boot with -d and set breakpoints using function names.
o Make sure to include opt_msgbuf.h.
o Carve out the first 1MB of physical memory. The MPC85xx has
DMA problems with addresses below 1MB. Ideally busdma knows how to avoid allocating below 1MB for MPC85xx, but that requires a bit more work. For now, ignore the 1MB of DRAM.