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-loadables.rst b/doc/usage/fit/multi-with-loadables.rst
new file mode 100644
index 0000000..a0241df
--- /dev/null
+++ b/doc/usage/fit/multi-with-loadables.rst
@@ -0,0 +1,91 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Multiple kernels, ramdisks and FDT blobs with Xen
+=================================================
+
+This example makes use of the 'loadables' field::
+
+    /dts-v1/;
+
+    / {
+        description = "Configuration to load a Xen Kernel";
+        #address-cells = <1>;
+
+        images {
+            xen_kernel {
+                description = "xen binary";
+                data = /incbin/("./xen");
+                type = "kernel";
+                arch = "arm";
+                os = "linux";
+                compression = "none";
+                load = <0xa0000000>;
+                entry = <0xa0000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            fdt-1 {
+                description = "xexpress-ca15 tree blob";
+                data = /incbin/("./vexpress-v2p-ca15-tc1.dtb");
+                type = "flat_dt";
+                arch = "arm";
+                compression = "none";
+                load = <0xb0000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            fdt-2 {
+                description = "xexpress-ca15 tree blob";
+                data = /incbin/("./vexpress-v2p-ca15-tc1.dtb");
+                type = "flat_dt";
+                arch = "arm";
+                compression = "none";
+                load = <0xb0400000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            linux_kernel {
+                description = "Linux Image";
+                data = /incbin/("./Image");
+                type = "kernel";
+                arch = "arm";
+                os = "linux";
+                compression = "none";
+                load = <0xa0000000>;
+                entry = <0xa0000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+        };
+
+        configurations {
+            default = "config-2";
+
+            config-1 {
+                description = "Just plain Linux";
+                kernel = "linux_kernel";
+                fdt = "fdt-1";
+            };
+
+            config-2 {
+                description = "Xen one loadable";
+                kernel = "xen_kernel";
+                fdt = "fdt-1";
+                loadables = "linux_kernel";
+            };
+
+            config-3 {
+                description = "Xen two loadables";
+                kernel = "xen_kernel";
+                fdt = "fdt-1";
+                loadables = "linux_kernel", "fdt-2";
+            };
+        };
+    };