Add usb otg data node in omap4/omap3 device tree file. Also update
the node with board specific setting in omapx-<board>.dts file.
The dt data specifies among others the interface type (ULPI or UTMI),
mode which is mostly OTG, power that specifies the amount of power
this can supply when in host mode.

The information about usb otg node is available @
Documentation/devicetree/bindings/usb/omap-usb.txt
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Benoit Cousson <benoit.cousson@linaro.org>