Optimize SPARC T4 MONTMUL support.

Improve RSA sing performance by 20-30% by:
- switching from floating-point to integer conditional moves;
- daisy-chaining sqr-sqr-sqr-sqr-sqr-mul sequences;
- using MONTMUL even during powers table setup;
(cherry picked from commit 4ddacd9921f48013b5cd011e4b93b294c14db1c2)
SPARC T4 DES support: fix typo.
(cherry picked from commit 8ee3c7e676c5edb1d5fbe0d66b7ce307a4f92899)