Spell diskcontroller as disk controller.
There is no more CMD640 option.
bad144 got axed. Reflect change.
Contract the /dev entries to one /dev/wd* entry which we call
wd device nodes to reflect the merger of character and block
devices.
Add small line to NOTES stating that wd will some be replaced
completely by ata/ad.
Suggested by: bde
7fe44daeda