crypto: drbg - Remove support for HASH_DRBG

crypto: drbg - Remove support for HASH_DRBG

Remove the support for HASH_DRBG.  It's likely unused code, seeing as
HMAC_DRBG is always enabled and prioritized over it unless
NETLINK_CRYPTO is used to change the algorithm priorities.

There's also no compelling reason to support more than one of
[HMAC_DRBG, HASH_DRBG, CTR_DRBG].  By definition, callers cannot tell
any difference in their outputs.  And all are FIPS-certifiable, which is
the only point of the kernel's NIST DRBGs anyway.

Switching to HASH_DRBG doesn't seem all that compelling, either.  For
one, it's more complex than HMAC_DRBG.

Thus, let's just drop HASH_DRBG support and focus on HMAC_DRBG.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>