KEYS: Provide missing asymmetric key subops for new key type ops [ver #2]
Provide the missing asymmetric key subops for new key type ops. This
include query, encrypt, decrypt and create signature. Verify signature
already exists. Also provided are accessor functions for this:
int query_asymmetric_key(const struct key *key,
struct kernel_pkey_query *info);
int encrypt_blob(struct kernel_pkey_params *params,
const void *data, void *enc);
int decrypt_blob(struct kernel_pkey_params *params,
const void *enc, void *data);
int create_signature(struct kernel_pkey_params *params,
const void *data, void *enc);
The public_key_signature struct gains an encoding field to carry the
encoding for verify_signature().