copper: use dtb address from image header

Change-Id: I3b17cd2d295839b97746052849440dcff8e59ad0
diff --git a/app/aboot/aboot.c b/app/aboot/aboot.c
index c8c7e17..dbcd8dd 100644
--- a/app/aboot/aboot.c
+++ b/app/aboot/aboot.c
@@ -628,7 +628,6 @@
 			}
 
 			/* Read device device tree in the "tags_add */
-			hdr->tags_addr = 0x8400000;
 			if(mmc_read(ptn + offset + dt_entry_ptr->offset,
 						 (void *)hdr->tags_addr, dt_entry_ptr->size)) {
 				dprintf(CRITICAL, "ERROR: Cannot read device tree\n");