* we remove the paritition 0 from ->part[] and put the old
contents of ->part[0] into gendisk itself; indexes are shifted, obviously.
	* ->part is allocated at add_gendisk() time and freed at del_gendisk()
according to value of ->minor_shift; static arrays of hd_struct are gone
from drivers, ditto for manual allocations a-la ide.  As the matter of fact,
none of the drivers know about struct hd_struct now.