thunderbolt: Use HMAC-SHA256 library instead of crypto_shash

thunderbolt: Use HMAC-SHA256 library instead of crypto_shash

Use the hmac_sha256_usingrawkey() library function instead of the
"hmac(sha256)" crypto_shash.  This is simpler and faster.

As a cleanup, change the input data parameters from "challenge,
sizeof(hmac)" to "challenge, sizeof(challenge)", so that the size is
being taken of the correct buffer.  This is not a functional change,
since it happens that sizeof(hmac) == sizeof(challenge).

Replace the selection of CRYPTO and CRYPTO_HASH with CRYPTO_LIB_SHA256
and CRYPTO_LIB_UTILS.  The latter is needed for crypto_memneq() which
was previously being pulled in via CRYPTO.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>