ARM: dts: am33xx: Add control module syscon node

Use syscon regmap to expose the Control module register space.
This register space is shared between many users e.g. DCAN, USB, display, etc.

Signed-off-by: Roger Quadros <rogerq@ti.com>
ARM: dts: am33xx: Add dcan raminit bits

Add RAMINIT specific bits into the DCAN nodes.
Also rename can nodes from "d_can" to "can" to be compliant
with the ePAPR specs.

Signed-off-by: Roger Quadros <rogerq@ti.com>