Fix bug in clear_motion()

memset used in clear_motion() is modified to set
inlier_indices appropriately.

Change-Id: I1344eb3d04af6d15a5ef4046597eb759721f39dc
diff --git a/av1/encoder/ransac.c b/av1/encoder/ransac.c
index 6180f13..685d93b 100644
--- a/av1/encoder/ransac.c
+++ b/av1/encoder/ransac.c
@@ -366,7 +366,7 @@
   motion->num_inliers = 0;
   motion->variance = kInfiniteVariance;
   memset(motion->inlier_indices, 0,
-         sizeof(*motion->inlier_indices * num_points));
+         sizeof(*motion->inlier_indices) * num_points);
 }
 
 static int ransac(const int *matched_points, int npoints,