dt-bindings: Add devicetree bindings

Add snapshot of device tree bindings from keystone common kernel, branch
"android-mainline-keystone-qcom-release" at c4c12103f9c0 ("Snap for 9228065
from e32903b9a63bb558df8b803b076619c53c16baad to
android-mainline-keystone-qcom-release").

Change-Id: I7682079615cbd9f29340a5c1f2a1d84ec441a1f1
Signed-off-by: Melody Olvera <quic_molvera@quicinc.com>

bindings/fpga/altera-fpga2sdram-bridge.txt

@@ -0,0 +1,13 @@
+Altera FPGA To SDRAM Bridge Driver
+
+Required properties:
+- compatible		: Should contain "altr,socfpga-fpga2sdram-bridge"
+
+See Documentation/devicetree/bindings/fpga/fpga-bridge.txt for generic bindings.
+
+Example:
+	fpga_bridge3: fpga-bridge@ffc25080 {
+		compatible = "altr,socfpga-fpga2sdram-bridge";
+		reg = <0xffc25080 0x4>;
+		bridge-enable = <0>;
+	};