sasl_gssapi: Added missing function description

lib/curl_sasl_gssapi.c

@@ -332,6 +332,16 @@ CURLcode Curl_sasl_create_gssapi_security_message(struct SessionHandle *data,
   return result;
 }
 
+/*
+* Curl_sasl_gssapi_cleanup()
+*
+* This is used to clean up the gssapi specific data.
+*
+* Parameters:
+*
+* krb5     [in/out] - The kerberos 5 data struct being cleaned up.
+*
+*/
 void Curl_sasl_gssapi_cleanup(struct kerberos5data *krb5)
 {
   OM_uint32 minor_status;