[PATCH] Fix unwinder warning in traps.c

Fix

linux/arch/x86_64/kernel/traps.c: In function 'dump_trace':
linux/arch/x86_64/kernel/traps.c:275: warning: cast to pointer from integer of different size

with allnoconfig

Cc: jbeulich@novell.com
Signed-off-by: Andi Kleen <ak@suse.de>