dts: bindings: dma: intel_lpss: Added phandle dma-parent

Added a phandle named dma-parent to get base address instead of
adding DMA as child node because it is causing a build warning
(avoid_unnecessary_addr_size) if the parent instance has
"#address-cells/#size-cells" dts properties marked required
and child doesn't have reg property. DMA doesn't have reg
as it gets the base address from parent device

Signed-off-by: Anisetti Avinash Krishna <anisetti.avinash.krishna@intel.com>

dts/bindings/dma/intel,lpss.yaml

@@ -11,5 +11,10 @@ properties:
   "#dma-cells":
     const: 1
 
+  dma-parent:
+    type: phandle
+    description: |
+      Parent device for LPSS DMA to get its base address.
+
 dma-cells:
   - channel