[CRYPTO] api: Add crypto_attr_alg_name

This patch adds a new helper crypto_attr_alg_name which is basically the
first half of crypto_attr_alg.  That is, it returns an algorithm name
parameter as a string without looking it up.  The caller can then look it
up immediately or defer it until later.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index 2cdb227..726a765 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -113,6 +113,7 @@
 
 struct crypto_attr_type *crypto_get_attr_type(struct rtattr **tb);
 int crypto_check_attr_type(struct rtattr **tb, u32 type);
+const char *crypto_attr_alg_name(struct rtattr *rta);
 struct crypto_alg *crypto_attr_alg(struct rtattr *rta, u32 type, u32 mask);
 int crypto_attr_u32(struct rtattr *rta, u32 *num);
 struct crypto_instance *crypto_alloc_instance(const char *name,