ARM: dts: Configure interconnect target module for am437x dispc

ARM: dts: Configure interconnect target module for am437x dispc

We can now probe devices with device tree only configuration using
ti-sysc interconnect target module driver. Let's configure the
module, but keep the legacy "ti,hwmods" peroperty until the child
devices are probing with ti-sysc interconnect driver.

Note that we also fix a harmless typo for the node name, it's
dispc@400, not dispc@4000.

Cc: Jyri Sarha <jsarha@ti.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>