Use OD_ILOG_NZ in OD_DIVU_SMALL_CONSTS

If _d == 0 we are already off to the UB races due to out of bounds
access in OD_DIVU_SMALL_CONSTS.

Change-Id: I55a76c51483885bbb38667f14836be9830e130a8

av1/common/odintrin.h

diff --git a/av1/common/odintrin.h b/av1/common/odintrin.h
index bce576d..68a6f90 100644
--- a/av1/common/odintrin.h
+++ b/av1/common/odintrin.h
@@ -97,7 +97,7 @@
   ((uint32_t)((OD_DIVU_SMALL_CONSTS[(_d)-1][0] * (uint64_t)(_x) + \
                OD_DIVU_SMALL_CONSTS[(_d)-1][1]) >>                \
               32) >>                                              \
-   (OD_ILOG(_d) - 1))
+   (OD_ILOG_NZ(_d) - 1))
 
 #define OD_DIVU(_x, _d) \
   (((_d) < OD_DIVU_DMAX) ? (OD_DIVU_SMALL((_x), (_d))) : ((_x) / (_d)))