Use crypto_shash_digest() instead of crypto_shash_init() +
crypto_shash_update() + crypto_shash_final().  This is more efficient.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>