ARM: OMAP2+: timer: Remove obsolete inclusion of <asm/smp_twd.h>

As of commit d1dabab2 ("ARM: OMAP2+: Clean up
omap4_local_timer_init"), this header file is no longer used.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Tony Lindgren <tony@atomide.com>