security/keys: Remove inconsistent __user annotation

The declaration of keyring_read does not match the definition
(security/keys/keyring.c). In this case the definition is correct
because it matches what defined in "struct key_type::read"
(linux/key-type.h).

Fix the declaration removing the inconsistent __user annotation.

Cc: David Howells <dhowells@redhat.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

security/keys/keyring.c

@@ -79,7 +79,7 @@ static void keyring_revoke(struct key *keyring);
 static void keyring_destroy(struct key *keyring);
 static void keyring_describe(const struct key *keyring, struct seq_file *m);
 static long keyring_read(const struct key *keyring,
-			 char __user *buffer, size_t buflen);
+			 char *buffer, size_t buflen);
 
 struct key_type key_type_keyring = {
 	.name		= "keyring",