Fix mips32 dspr2 build warnings.

Change-Id: Iadbb91ca1905318f094fdfae95f2c4db87943842
diff --git a/aom_dsp/mips/intrapred16_dspr2.c b/aom_dsp/mips/intrapred16_dspr2.c
index dc8f2020..7c221ae 100644
--- a/aom_dsp/mips/intrapred16_dspr2.c
+++ b/aom_dsp/mips/intrapred16_dspr2.c
@@ -17,6 +17,8 @@
   int32_t tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8;
   int32_t tmp9, tmp10, tmp11, tmp12, tmp13, tmp14, tmp15, tmp16;
 
+  (void)above;
+
   __asm__ __volatile__(
       "lb         %[tmp1],      (%[left])                    \n\t"
       "lb         %[tmp2],      1(%[left])                   \n\t"