ARM: OMAP4: Add local timer support for Device Tree

Add cortex-a9 local timer support for all OMAP4 based
SOCs using DT.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Benoit Cousson <b-cousson@ti.com>