X.509: Need to export x509_request_asymmetric_key()

Need to export x509_request_asymmetric_key() so that PKCS#7 can use it if
compiled as a module.

Reported-by: James Morris <jmorris@namei.org>
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index da1e5fc..f3d6230 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -96,6 +96,7 @@
 		 key_serial(key_ref_to_ptr(key)));
 	return key_ref_to_ptr(key);
 }
+EXPORT_SYMBOL_GPL(x509_request_asymmetric_key);
 
 /*
  * Set up the signature parameters in an X.509 certificate.  This involves