imx: imx7d-sdb: Add DM QSPI support

On iMX7D SabreSD board, the QSPI has pins conflict with EPDC (default).
To use QSPI, users have to rework the board (de-populate R388-R391, R396-R399
populate R392-R395, R299, R300). So we add new DTS file and new defconfig
dedicated for QSPI.

Other changes to support the DM QSPI:
 - Add QSPI node and alias spi0.
 - Modify spi4 (spi-gpio) node and add alias spi5 for it to avoid req
   conflict
 - Add EPDC node in imx7d.dtsi and disable it in imx7d-sdb-qspi.dts to
   align with kernel and also present the conflict.
 - Add -u-boot.dtsi to modify compatible string of mx25l51245g@0 to
   "spi-flash"
 - Remove iomux settings of qspi in board codes which is not needed
   for DM driver.

Signed-off-by: Ye Li <ye.li@nxp.com>
diff --git a/arch/arm/dts/imx7d.dtsi b/arch/arm/dts/imx7d.dtsi
index f6dee41..30b0589 100644
--- a/arch/arm/dts/imx7d.dtsi
+++ b/arch/arm/dts/imx7d.dtsi
@@ -86,6 +86,18 @@
 	};
 };
 
+&aips2 {
+	epdc: epdc@306f0000 {
+		compatible = "fsl,imx7d-epdc";
+		interrupts = <GIC_SPI 117 IRQ_TYPE_LEVEL_HIGH>;
+		reg = <0x306f0000 0x10000>;
+		clocks = <&clks IMX7D_CLK_DUMMY>, <&clks IMX7D_EPDC_PIXEL_ROOT_CLK>;
+		clock-names = "epdc_axi", "epdc_pix";
+		epdc-ram = <&gpr 0x4 30>;
+		status = "disabled";
+	};
+};
+
 &aips3 {
 	usbotg2: usb@30b20000 {
 		compatible = "fsl,imx7d-usb", "fsl,imx27-usb";