Pull up following revision(s) (requested by mrg in ticket #1411):
sys/kern/subr_disk.c: revision 1.100
add some (uint64_t) casts so avoid 32 bit overflows.  this fixes my
3TB disk with 4KB sectors and disklabel (which looks like it would
work upto 16TB.)
idea from mlelstv@.

(riz)