boards: opta: allow memory mapping external QSPI flash

This commit enable QSPI flash memory mapping on OPTA

Signed-off-by: Mattia Pennasilico <[email protected]>

Author: pennam

boards/arduino/opta/arduino_opta_stm32h747xx_m7.dts

@@ -21,6 +21,14 @@
 		zephyr,code-partition = &slot0_partition;
 		zephyr,bt-hci = &bt_hci_uart;
 	};
+
+	ext_memory: memory@90000000 {
+		compatible = "zephyr,memory-region";
+		reg = <0x90000000 DT_SIZE_M(16)>; /* max addressable area */
+		zephyr,memory-region = "EXTMEM";
+		/* The ATTR_MPU_EXTMEM attribut causing a MPU FAULT */
+		zephyr,memory-attr = <( DT_MEM_ARM(ATTR_MPU_IO) )>;
+	};
 };
 
 zephyr_udc0: &usbotg_fs {