ARM: OMAP2+: Divorce from local timer API

Now that the TWD doesn't rely on the local timer API, OMAP can
stop selecting it in Kconfig and relying on the config option to
decide if it should call smp_twd functions.

Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>