Fix MIPS linker build

(cherry-picked from 8c7d8c2057e303985f78eab96da747ddaa013c78)

Change-Id: Idcf62ab95f8fccbc2d7c3e771a4cfbe768a1555e
diff --git a/linker/linker.cpp b/linker/linker.cpp
index f18443c..db0c9f1 100755
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -1487,7 +1487,7 @@
             break;
 
         default:
-            DEBUG("Unused DT entry: type 0x%08x arg 0x%08x\n", d[-1], d[0]);
+            DEBUG("Unused DT entry: type 0x%08x arg 0x%08x\n", d->d_tag, d->d_un.d_val);
             break;
 #endif
         }