[nrf fromtree] boards: nordic: nrf54h20dk: add DMA attribute to RAM21 & RAM3x

This attribute denotes that DMA operation
can be performed from a given region.

Signed-off-by: Nikodem Kastelik <[email protected]>
(cherry picked from commit ea361f0)

Author: nika-nordic

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20-memory_map.dtsi

@@ -110,7 +110,7 @@
 				status = "disabled";
 				#memory-region-cells = <0>;
 				zephyr,memory-region = "DMA_RAM21";
-				zephyr,memory-attr = <( DT_MEM_CACHEABLE )>;
+				zephyr,memory-attr = <( DT_MEM_DMA | DT_MEM_CACHEABLE )>;
 			};
 		};
 
@@ -154,6 +154,7 @@
 				status = "disabled";
 				#memory-region-cells = <0>;
 				zephyr,memory-region = "DMA_RAM3x_APP";
+				zephyr,memory-attr = <( DT_MEM_DMA )>;
 			};
 
 			cpurad_dma_region: memory@1e80 {
@@ -162,6 +163,7 @@
 				status = "disabled";
 				#memory-region-cells = <0>;
 				zephyr,memory-region = "DMA_RAM3x_RAD";
+				zephyr,memory-attr = <( DT_MEM_DMA )>;
 			};
 		};
 	};