sim: constify save_data()

The local save_data() function takes a pointer to a buffer and only uses it as
the source to the memcpy() function.  Since it is given const strings, GCC
likes to spit out warnings:
common/sim-trace.c: In function 'trace_prefix':
common/sim-trace.c:697: warning: passing argument 5 of 'save_data' discards
	qualifiers from pointer target type

So I've committed this as obvious.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

sim/common/ChangeLog

@@ -1,3 +1,7 @@
+2010-04-10  Mike Frysinger  <vapier@gentoo.org>
+
+	* sim-trace.c (save_data): Add const markings to "buf" argument.
+
 2010-04-10  Mike Frysinger  <vapier@gentoo.org>
 
 	* sim-options.c (standard_option_handler): Add const markings to

sim/common/sim-trace.c

@@ -513,7 +513,7 @@ save_data (SIM_DESC sd,
 	   TRACE_DATA *data,
 	   data_fmt fmt,
 	   long size,
-	   void *buf)
+	   const void *buf)
 {
   int i = TRACE_INPUT_IDX (data);
   if (i == sizeof (TRACE_INPUT_FMT (data)))