Add `sim_complete_command' definition to erc32 sim

This patch fixes a build failure at link time due to
sim_complete_command being undefined.  There was a recent change
that added this function to all the ports that do not use the
common/ subdir.  But somehow, the erc32 port got missed.

sim/erc32/ChangeLog:

        * interf.c (sim_complete_command): New stub function.

sim/erc32/ChangeLog

@@ -1,3 +1,7 @@
+2011-06-01  Joel Brobecker  <brobecker@adacore.com>
+
+	* interf.c (sim_complete_command): New stub function.
+
 2011-01-11  Andrew Burgess  <aburgess@broadcom.com>
 
 	* interf.c (sim_store_register): Update return value to

sim/erc32/interf.c

@@ -481,6 +481,12 @@ sim_do_command(sd, cmd)
     exec_cmd(&sregs, cmd);
 }
 
+char **
+sim_complete_command (SIM_DESC sd, char *text, char *word)
+{
+  return NULL;
+}
+
 #if 0 /* FIXME: These shouldn't exist.  */
 
 int