boards: mimxrt11xx: Enable Flash driver on RT1160 and RT1170

Enable the flash on RT1170 and RT1160. When booting from the CM7 core,
flash will be started in XIP mode and used as storage as well as boot
memory. When booting from the CM4 core, flash is available as storage
only, and does not run in XIP mode.

This commit was tested with the following samples
-flash_shell
-littlefs

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>

boards/arm/mimxrt1160_evk/mimxrt1160_evk_cm4.dts

@@ -17,6 +17,8 @@
 		zephyr,sram = &sram1;
 		zephyr,console = &lpuart1;
 		zephyr,shell-uart = &lpuart1;
+		zephyr,flash-controller = &flexspi;
+		zephyr,flash = &is25wp128;
 	};
 
 
@@ -36,3 +38,49 @@
 &lpi2c1 {
 	status = "okay";
 };
+
+&flexspi {
+	status = "okay";
+	ahb-prefetch;
+	ahb-read-addr-opt;
+	rx-clock-source = <1>;
+	reg = <0x400cc000 0x4000>, <0x30000000 DT_SIZE_M(16)>;
+	is25wp128: is25wp128@0 {
+		compatible = "nxp,imx-flexspi-nor";
+		size = <134217728>;
+		label = "IS25WP128";
+		reg = <0>;
+		spi-max-frequency = <133000000>;
+		status = "okay";
+		jedec-id = [9d 70 17];
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+			/* Note: CM4 does not boot from flexspi, but CM7 code will be
+			 * stored in slot0
+			 */
+			boot_partition: partition@0 {
+				label = "mcuboot";
+				reg = <0x00000000 DT_SIZE_K(64)>;
+			};
+			slot0_partition: partition@10000 {
+				label = "image-0";
+				reg = <0x00010000 DT_SIZE_M(3)>;
+			};
+			slot1_partition: partition@310000 {
+				label = "image-1";
+				reg = <0x00310000 DT_SIZE_M(3)>;
+			};
+			scratch_partition: partition@610000 {
+				label = "image-scratch";
+				reg = <0x00610000 DT_SIZE_K(128)>;
+			};
+			storage_partition: partition@630000 {
+				label = "storage";
+				reg = <0x00630000 DT_SIZE_K(1856)>;
+			};
+		};
+	};
+};