ARM: dts: Configure interconnect target module for dra7 tptc0

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.

Let's also correct the custom node name to use generic node name dma.

Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>