KEYS: Restore partial ID matching functionality for asymmetric keys

Bring back the functionality whereby an asymmetric key can be matched with a
partial match on one of its IDs.

Whilst we're at it, allow for the possibility of having an increased number of
IDs.

Reported-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h
index 044ab0d..c0754ab 100644
--- a/include/keys/asymmetric-type.h
+++ b/include/keys/asymmetric-type.h
@@ -51,6 +51,9 @@
 extern bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
 				   const struct asymmetric_key_id *kid2);
 
+extern bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
+				      const struct asymmetric_key_id *kid2);
+
 extern struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
 							    size_t len_1,
 							    const void *val_2,