* Split bios geometry and MBR partition editing code formerly in
arch/i386/{md,fdisk}.c to mbr.c in mi directory.
* Leave /sbin/fdisk parsing/handling code in separate file,
we may want to change it later. move to mi directory.
* Create mbr.h with declarations for MBR/BIOS-geomotry code.
#include "mbr.h" in i386 md.h.
* Use symbolic names for 386bsd and new NetBSD partition IDs.
Handle MBRs with both 386bsd and NetBSD partitions less stupidly.
