boards: st: stm32n6570_dk: set mem attr in psram area

Add MEM_SW_ATTR on the PSRAM memory in order to have it
become accessible via the mem_attr_heap framework.
On this device since we need to allocate a rather large
framebuffer, we can do that on the PSRAM memory.

Signed-off-by: Alain Volmat <[email protected]>

Author: Alain Volmat

boards/st/stm32n6570_dk/stm32n6570_dk_common.dtsi

@@ -42,7 +42,7 @@
 		compatible = "zephyr,memory-region";
 		reg = <0x90000000 DT_SIZE_M(32)>;
 		zephyr,memory-region = "PSRAM";
-		zephyr,memory-attr = <( DT_MEM_ARM(ATTR_MPU_RAM) )>;
+		zephyr,memory-attr = <( DT_MEM_ARM(ATTR_MPU_RAM) | DT_MEM_SW_ALLOC_CACHE )>;
 	};
 
 	leds: leds {