crypto: sahara - remove dependency on EXPERIMENTAL

The Kconfig symbol EXPERIMENTAL was removed in v3.9. So this dependency
makes it impossible to set CRYPTO_DEV_SAHARA. It's unlikely that this is
what is intended, so let's remove this dependency.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>