ARM: OMAP2+: Add minimal clockdomains for dm814x

For now, let's just add the ones shared with dm816x.
The dm814x specific ones can be added as they are tested.

Cc: Matthijs van Duin <matthijsvanduin@gmail.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>