10132 smatch fixes for MDB
Reviewed by: Andy Fiddaman <andy@omniosce.org>

@@ -22,11 +22,11 @@
  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 /*
  * Copyright (c) 2012 by Delphix. All rights reserved.
- * Copyright (c) 2012 Joyent, Inc. All rights reserved.
+ * Copyright (c) 2018, Joyent, Inc.
  */
 
 /*
  * Modular Debugger (MDB)
  *

@@ -1153,11 +1153,11 @@
     uintmax_t argc, mdb_arg_t *argv)
 {
         if (idcp->idc_tabp == NULL)
                 return;
 
-        idcp->idc_tabp(mcp, flags, argc, argv);
+        (void) idcp->idc_tabp(mcp, flags, argc, argv);
 }
 
 /*
  * Call an internal dcmd directly: this code is used by module API functions
  * that need to execute dcmds, and by mdb_call() above.