MIPS: Lantiq: Add device_tree_init function

Add a lantiq specific version of device_tree_init. The generic MIPS version
was removed by.

commit 594e966bc412d64eec9282d28ce511bdd62fea39
Author: David Daney <david.daney@cavium.com>
Date:   Thu Jul 5 18:12:38 2012 +0200

MIPS: Prune some target specific code out of prom.c

Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/4116/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/lantiq/prom.c

@@ -8,7 +8,10 @@
 
 #include <linux/export.h>
 #include <linux/clk.h>
+#include <linux/bootmem.h>
 #include <linux/of_platform.h>
+#include <linux/of_fdt.h>
+
 #include <asm/bootinfo.h>
 #include <asm/time.h>
 
@@ -70,6 +73,25 @@ void __init plat_mem_setup(void)
 	__dt_setup_arch(&__dtb_start);
 }
 
+void __init device_tree_init(void)
+{
+	unsigned long base, size;
+
+	if (!initial_boot_params)
+		return;
+
+	base = virt_to_phys((void *)initial_boot_params);
+	size = be32_to_cpu(initial_boot_params->totalsize);
+
+	/* Before we do anything, lets reserve the dt blob */
+	reserve_bootmem(base, size, BOOTMEM_DEFAULT);
+
+	unflatten_device_tree();
+
+	/* free the space reserved for the dt blob */
+	free_bootmem(base, size);
+}
+
 void __init prom_init(void)
 {
 	/* call the soc specific detetcion code and get it to fill soc_info */