ARM: dts: sbc-t3517: add support for sbc-t3517

Add support for CM-T3517 CoM and SBC-T3517 board.

reused common support for sbc-t3x boards
(omap3-cm-t3x.dtsi, omap3-sb-t35.dtsi):

* SB-T35 baseboard eth
* MMC1, UART3
* HS USB Port 1/2
* I2C1/3
* Heartbit led

Added basic support for:

* MMC1 wp/cd signals
* CM-T3517 Usb Hub
* WL12xx WiFi chip
* Davinci EMAC
* AM35X OTG

Signed-off-by: Dmitry Lifshitz <lifshitz@compulab.co.il>
Signed-off-by: Tony Lindgren <tony@atomide.com>