cylinder, head and track numbers. Return ~0U for these values when
mkimg wasn't given both -T and -H (i.e. no geometry) or the cylinder
would be larger than the provided maximum.
Use mkimgs_chs() for the EBR, MBR and PC98 schemes to fill in the
appropriate fields. Make sure to use a "rounded" size so that the
partition is always a multiple of the track size. We reserved the
room for it in the metadata callback so that's a valid thing to
do.
Bump the mkimg version number.
While doing that again: have mkimg.o depend on the Makefile so that
a version change triggers a rebuild as needed.