math/lapack: remove superfluous and broken ranlib invocation

FreeBSD's base system ar and ranlib have a bug where they exit with
status 0 (success) even in case of fatal errors. This hid the fact that
math/lapacke was invoking ranlib on a non-existent file. (Presumably the
ranlib invocation was correct when introduced, but broken by some
rework of lapack's upstream build system).

Use of ranlib is generally unncessary, assuming the -s flag is passed to
ar (as is typical, and as done here), so just delete the invocation.

See PR 257599 and review D31402 for the ar/ranlib base system bug.

PR: 257599, 257744
Reviewed by: jrm
Tested by: jrm
Approved by: kevans (ports), portmgr (implicit, blanket: build fix)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31492