The *_meta_* functions include a radix parameter, a blk parameter, and
another parameter that identifies a starting point in the memory address
block. Radix is a power of two, blk is a multiple of radix, and the
starting point is in the range [blk, blk+radix), so that blk can always be
computed from the other two. This change drops the blk parameter from the
meta functions and computes it instead. (On amd64, for example, this
change reduces subr_blist.o's text size by 7%.)

It also makes the radix parameters unsigned to address concerns that the
calculation of '-radix' might overflow without the -fwrapv option. (See
https://reviews.freebsd.org/D11819.)

Submitted by: Doug Moore <dougm@rice.edu>
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D11964