x86: use unflatten_and_copy_device_tree

Use the common unflatten_and_copy_device_tree to copy the built-in FDT
out of init section.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org

arch/x86/kernel/devicetree.c

@@ -230,7 +230,7 @@ static void __init dtb_apic_setup(void)
 static void __init x86_flattree_get_config(void)
 {
 	u32 size, map_len;
-	void *new_dtb;
+	struct boot_param_header *dt;
 
 	if (!initial_dtb)
 		return;
@@ -238,24 +238,17 @@ static void __init x86_flattree_get_config(void)
 	map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK),
 			(u64)sizeof(struct boot_param_header));
 
-	initial_boot_params = early_memremap(initial_dtb, map_len);
-	size = be32_to_cpu(initial_boot_params->totalsize);
+	dt = early_memremap(initial_dtb, map_len);
+	size = be32_to_cpu(dt->totalsize);
 	if (map_len < size) {
-		early_iounmap(initial_boot_params, map_len);
-		initial_boot_params = early_memremap(initial_dtb, size);
+		early_iounmap(dt, map_len);
+		dt = early_memremap(initial_dtb, size);
 		map_len = size;
 	}
 
-	new_dtb = alloc_bootmem(size);
-	memcpy(new_dtb, initial_boot_params, size);
-	early_iounmap(initial_boot_params, map_len);
-
-	initial_boot_params = new_dtb;
-
-	/* root level address cells */
-	of_scan_flat_dt(early_init_dt_scan_root, NULL);
-
-	unflatten_device_tree();
+	initial_boot_params = dt;
+	unflatten_and_copy_device_tree();
+	early_iounmap(dt, map_len);
 }
 #else
 static inline void x86_flattree_get_config(void) { }