Add DM timer support for OMAP3.

Fixed source clocks for 3430 by Paul Walmsley <paul@pwsan.com>.
Signed-off-by: NSyed Mohammed Khasim <x0khasim@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>