ARM: dts: dra7: Add USB related nodes

Add nodes for the Super Speed USB controllers, omap-control-usb,
USB2 PHY and USB3 PHY devices.

Remove ocp2scp1 address space from hwmod data as it is
now provided via device tree.

CC: Benoît Cousson <bcousson@baylibre.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>