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/board/freescale/imx91_evk/Kconfig b/board/freescale/imx91_evk/Kconfig
new file mode 100644
index 0000000..caaa82b
--- /dev/null
+++ b/board/freescale/imx91_evk/Kconfig
@@ -0,0 +1,19 @@
+if TARGET_IMX91_11X11_EVK
+
+config SYS_BOARD
+	default "imx91_evk"
+
+config SYS_VENDOR
+	default "freescale"
+
+config SYS_CONFIG_NAME
+	default "imx91_evk"
+
+config IMX91_EVK_LPDDR4
+	bool "Using LPDDR4 Timing and PMIC voltage"
+	default y
+	select IMX9_LPDDR4X
+	help
+	  Select the LPDDR4 timing and 1.1V VDDQ
+
+endif