fix the following 'make includecheck' warning:

  arch/x86/kernel/traps.c: asm/traps.h is included more than once.
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Sam Ravnborg <sam@ravnborg.org>
LKML-Reference: <1247065094.4382.49.camel@ht.satnam>