[PATCH] ppc32: update xmon help text

Mention a few more commands in xmon.  System.map processing was replaced
with kallsyms.

Signed-off-by: Olaf Hering <olh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>