imx: Support i.MX91 11x11 EVK board

Add i.MX91 11x11 EVK Board support.
 - Four ddr scripts included w/o inline ecc feature.
 - SDHC/NETWORK/I2C/UART supported
 - PCA9451 supported, default nominal drive mode
 - Documentation added.

Signed-off-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/dts/imx91-u-boot.dtsi b/arch/arm/dts/imx91-u-boot.dtsi
new file mode 100644
index 0000000..5b639c9
--- /dev/null
+++ b/arch/arm/dts/imx91-u-boot.dtsi
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2023 Mathieu Othacehe <m.othacehe@gmail.com>
+ */
+
+/ {
+	binman: binman {
+		multiple-images;
+	};
+};
+
+&A55_0 {
+	clocks = <&clk IMX93_CLK_A55_SEL>;
+};
+
+&binman {
+	u-boot-spl-ddr {
+		align = <4>;
+		align-size = <4>;
+		filename = "u-boot-spl-ddr.bin";
+		pad-byte = <0xff>;
+
+		u-boot-spl {
+			align-end = <4>;
+			filename = "u-boot-spl.bin";
+		};
+
+		ddr-1d-imem-fw {
+			filename = "lpddr4_imem_1d_v202201.bin";
+			align-end = <4>;
+			type = "blob-ext";
+		};
+
+		ddr-1d-dmem-fw {
+			filename = "lpddr4_dmem_1d_v202201.bin";
+			align-end = <4>;
+			type = "blob-ext";
+		};
+
+		ddr-2d-imem-fw {
+			filename = "lpddr4_imem_2d_v202201.bin";
+			align-end = <4>;
+			type = "blob-ext";
+		};
+
+		ddr-2d-dmem-fw {
+			filename = "lpddr4_dmem_2d_v202201.bin";
+			align-end = <4>;
+			type = "blob-ext";
+		};
+	};
+
+	spl {
+		filename = "spl.bin";
+
+		mkimage {
+			args = "-n spl/u-boot-spl.cfgout -T imx8image -e 0x204A0000";
+
+			blob {
+				filename = "u-boot-spl-ddr.bin";
+			};
+		};
+	};
+
+	u-boot-container {
+		filename = "u-boot-container.bin";
+
+		mkimage {
+			args = "-n u-boot-container.cfgout -T imx8image -e 0x0";
+
+			blob {
+				filename = "u-boot.bin";
+			};
+		};
+	};
+
+	imx-boot {
+		filename = "flash.bin";
+		pad-byte = <0x00>;
+
+		spl: blob-ext@1 {
+			filename = "spl.bin";
+			offset = <0x0>;
+			align-size = <0x400>;
+			align = <0x400>;
+		};
+
+		uboot: blob-ext@2 {
+			filename = "u-boot-container.bin";
+		};
+	};
+};