ARM: dts: Configure interconnect target module for omap2 sdma

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 to avoid new boot
time warnings. The legacy property will be removed in later patches
together with the legacy platform data.

Note that we want to use separate compatible for omap2420 and
omap2430 so let's do that here too while at it.

Cc: devicetree@vger.kernel.org
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Vinod Koul <vkoul@kernel.org>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>