perf symbols: Remove unused 'end' arg in kallsyms parse cb

kallsyms__parse() takes a callback that is called on every discovered
symbol. As /proc/kallsyms does not supply symbol sizes, the callback was
simply called with end=start, faking the symbol size to 1.

All of the callbacks (there are 2) used in calls to kallsyms__parse()
are _only_ used as callbacks for kallsyms__parse().

Given that kallsyms__parse() lacks real information about what
end/length should be, don't make up a length in kallsyms__parse().
Instead have the callbacks handle guessing the length.

Also relocate a comment regarding symbol creation to the callback which
does symbol creation (kallsyms__parse() is not in general used to create
symbols).

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Hansen <dave@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matt Hellsley <matthltc@us.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1344637382-22789-3-git-send-email-cody@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/event.c

@@ -412,7 +412,7 @@ struct process_symbol_args {
 };
 
 static int find_symbol_cb(void *arg, const char *name, char type,
-			  u64 start, u64 end __used)
+			  u64 start)
 {
 	struct process_symbol_args *args = arg;