dt-bindings: Document Tegra264 ADMA support

Add Tegra264 ADMA support to the device tree bindings documentation.
The Tegra264 ADMA hardware supports 64 DMA channels and requires
specific register configurations.

Signed-off-by: Sheetal <[e-mail]>
Acked-by: Conor Dooley <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

Documentation/devicetree/bindings/dma/nvidia,tegra210-adma.yaml

···
       - enum:
           - nvidia,tegra210-adma
           - nvidia,tegra186-adma
+          - nvidia,tegra264-adma
       - items:
           - enum:
               - nvidia,tegra234-adma
···
           contains:
             enum:
               - nvidia,tegra186-adma
+              - nvidia,tegra264-adma
     then:
       anyOf:
         - properties: