tracing: do not leak kernel addresses

This likely breaks tracing tools like trace-cmd.  It logs in the same
format but now addresses are all 0x0.

Bug: 34277115
Change-Id: Ifb0d4d2a184bf0d95726de05b1acee0287a375d9
Tracked-On: https://jira01.devtools.intel.com/browse/AW-5094


Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-on: https://android.intel.com/577968


Reviewed-by: Louis, FabienX <fabienx.louis@intel.com>
Tested-by: Louis, FabienX <fabienx.louis@intel.com>
Reviewed-by: Dubray, SimonX <simonx.dubray@intel.com>
Reviewed-by: Tasayco Loarte, VictorX <victorx.tasayco.loarte@intel.com>

kernel/trace/trace_printk.c

@@ -272,7 +272,7 @@ static int t_show(struct seq_file *m, void *v)
 	const char *str = *fmt;
 	int i;
 
-	seq_printf(m, "0x%lx : \"", *(unsigned long *)fmt);
+	seq_printf(m, "0x%lx : \"", 0L);
 
 	/*
 	 * Tabs and new lines need to be converted.