keys, trusted: select hash algorithm for TPM2 chips

Added 'hash=' option for selecting the hash algorithm for add_key()
syscall and documentation for it.

Added entry for sm3-256 to the following tables in order to support
TPM_ALG_SM3_256:

* hash_algo_name
* hash_digest_size

Includes support for the following hash algorithms:

* sha1
* sha256
* sha384
* sha512
* sm3-256

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>

crypto/hash_info.c

@@ -31,6 +31,7 @@ const char *const hash_algo_name[HASH_ALGO__LAST] = {
 	[HASH_ALGO_TGR_128]	= "tgr128",
 	[HASH_ALGO_TGR_160]	= "tgr160",
 	[HASH_ALGO_TGR_192]	= "tgr192",
+	[HASH_ALGO_SM3_256]	= "sm3-256",
 };
 EXPORT_SYMBOL_GPL(hash_algo_name);
 
@@ -52,5 +53,6 @@ const int hash_digest_size[HASH_ALGO__LAST] = {
 	[HASH_ALGO_TGR_128]	= TGR128_DIGEST_SIZE,
 	[HASH_ALGO_TGR_160]	= TGR160_DIGEST_SIZE,
 	[HASH_ALGO_TGR_192]	= TGR192_DIGEST_SIZE,
+	[HASH_ALGO_SM3_256]	= SM3256_DIGEST_SIZE,
 };
 EXPORT_SYMBOL_GPL(hash_digest_size);