dt/flattree: Return virtual address from early_init_dt_alloc_memory_arch()

The physical address is never used by the device tree code when
allocating memory for unflattening.  Change the architecture's alloc
hook to return the virutal address instead.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 9e3132d..7185f0d 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -519,9 +519,9 @@
 	memblock_add(base, size);
 }
 
-u64 __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
+void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
 {
-	return memblock_alloc(size, align);
+	return __va(memblock_alloc(size, align));
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD