doc: Bring in the FIT examples

Convert these to rST format and add them to the index.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/usage/fit/multi-with-fpga.rst b/doc/usage/fit/multi-with-fpga.rst
new file mode 100644
index 0000000..28d7d5d
--- /dev/null
+++ b/doc/usage/fit/multi-with-fpga.rst
@@ -0,0 +1,70 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Multiple kernels, ramdisks and FDT blobs with FPGA
+==================================================
+
+This example makes use of the 'loadables' field::
+
+    /dts-v1/;
+
+    / {
+        description = "Configuration to load fpga before Kernel";
+        #address-cells = <1>;
+
+        images {
+            fdt-1 {
+                description = "zc706";
+                data = /incbin/("/tftpboot/devicetree.dtb");
+                type = "flat_dt";
+                arch = "arm";
+                compression = "none";
+                load = <0x10000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            fpga {
+                description = "FPGA";
+                data = /incbin/("/tftpboot/download.bit");
+                type = "fpga";
+                arch = "arm";
+                compression = "none";
+                load = <0x30000000>;
+                compatible = "u-boot,fpga-legacy"
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            linux_kernel {
+                description = "Linux";
+                data = /incbin/("/tftpboot/zImage");
+                type = "kernel";
+                arch = "arm";
+                os = "linux";
+                compression = "none";
+                load = <0x8000>;
+                entry = <0x8000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+        };
+
+        configurations {
+            default = "config-2";
+            config-1 {
+                description = "Linux";
+                kernel = "linux_kernel";
+                fdt = "fdt-1";
+            };
+
+            config-2 {
+                description = "Linux with fpga";
+                kernel = "linux_kernel";
+                fdt = "fdt-1";
+                loadables = "fpga";
+            };
+        };
+    };