[PATCHv4 08/10] arm/dts: dra7.dtsi: add DSS support

* Tomi Valkeinen [off-list ref] [150531 23:25]:

DRA7xxx contains a very similar DSS to OMAP5. The main differences are:

* no DSI or RFBI support.
* 1 or 2 dedicated video PLLs.
* need to do additional configuration to the DRA7 CONTROL module.

DRA72xx has only one video PLL, and DRA74xx has two.

Signed-off-by: Tomi Valkeinen <redacted>
Cc: devicetree at vger.kernel.org

Acked-by: Tony Lindgren <tonY@atomide.com>