ARM: DTS: am437x: Use the new DT bindings for the eDMA3

ARM: DTS: am437x: Use the new DT bindings for the eDMA3

Switch to use the ti,edma3-tpcc and ti,edma3-tptc binding for the eDMA3 and
enable the DMA even crossbar with ti,am335x-edma-crossbar.
With the new bindings boards can customize and tweak the DMA channel
priority to match their needs. With the new binding the memcpy is safe
to be used since with the old binding it was not possible for a driver
to know which channel is allowed to be used as non HW triggered channel.

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