sparc: Remove optimize md5, sha256, and sha512

The libcrypt was maked to be phase out on 2.38, and a better project
already exist that provide both compatibility and better API
(libxcrypt).  The sparc optimizations add the burden to extra
build-many-glibcs.py configurations.

Checked on sparc64 and sparcv9.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>