fdt: move dumpdtb interpretation code to device_tree.c

The dumpdtb code can be useful in more places than just for e500. Move it
to a generic place.

Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/device_tree.c b/device_tree.c
index d7a9b6b..69ca953 100644
--- a/device_tree.c
+++ b/device_tree.c
@@ -304,3 +304,25 @@
     g_free(dupname);
     return retval;
 }
+
+void qemu_devtree_dumpdtb(void *fdt, int size)
+{
+    QemuOpts *machine_opts;
+
+    machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0);
+    if (machine_opts) {
+        const char *dumpdtb = qemu_opt_get(machine_opts, "dumpdtb");
+        if (dumpdtb) {
+            /* Dump the dtb to a file and quit */
+            FILE *f = fopen(dumpdtb, "wb");
+            size_t len;
+            len = fwrite(fdt, size, 1, f);
+            fclose(f);
+            if (len != size) {
+                exit(1);
+            }
+            exit(0);
+        }
+    }
+
+}