ARM: dts: am4372: Remove obsolete properties from edma node

dma-channels, ti,edma-regions and ti,edma-slots no longer needed in DT since
the the same information is available in the IP's CCCFG register.

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