KEYS: Remove key_type::match in favour of overriding default by match_preparse

A previous patch added a ->match_preparse() method to the key type.  This is
allowed to override the function called by the iteration algorithm.
Therefore, we can just set a default that simply checks for an exact match of
the key description with the original criterion data and allow match_preparse
to override it as needed.

The key_type::match op is then redundant and can be removed, as can the
user_match() function.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
static void rxrpc_free_token_list(struct rxrpc_key_token *token)
{
	struct rxrpc_key_token *next;

	for (; token; token = next) {
		next = token->next;
		switch (token->security_index) {
		case RXRPC_SECURITY_RXKAD:
			kfree(token->kad);
			break;
		case RXRPC_SECURITY_RXK5:
			if (token->k5)
				rxrpc_rxk5_free(token->k5);
			break;
		default:
			printk(KERN_ERR "Unknown token type %x on rxrpc key\n",
			       token->security_index);
			BUG();
		}

		kfree(token);
	}
}

static void rxrpc_free_token_list(struct rxrpc_key_token *token)
{
	struct rxrpc_key_token *next;

	for (; token; token = next) {
		next = token->next;
		switch (token->security_index) {
		case RXRPC_SECURITY_RXKAD:
			kfree(token->kad);
			break;
		case RXRPC_SECURITY_RXK5:
			if (token->k5)
				rxrpc_rxk5_free(token->k5);
			break;
		default:
			printk(KERN_ERR "Unknown token type %x on rxrpc key\n",
			       token->security_index);
			BUG();
		}

		kfree(token);
	}
}
