gostr3411_94: rewrite to use u32 mathematic

* cipher/gost28147.c (_gcry_gost_enc_data): New.
* cipher/gostr3411-94.c: Rewrite implementation to use u32 mathematic
  internally.
* cipher/gost28147.c (_gcry_gost_enc_one): Remove.

On my box (Core2 Duo, i386) this highly improves GOST R 34.11-94 speed.

Before:
GOSTR3411_94 | 55.04 ns/B 17.33 MiB/s - c/B

After:
GOSTR3411_94 | 36.70 ns/B 25.99 MiB/s - c/B

• Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>