Fix bug in qsort call of prepare_pack_bs_workers()

This CL fixes the sizeof() argument in qsort from pointer to
value, in the function prepare_pack_bs_workers().

Change-Id: I9e2122fb62487939c58e94596d95958fe74c2c01

av1/encoder/ethread.c

diff --git a/av1/encoder/ethread.c b/av1/encoder/ethread.c
index e548402..ce5a672 100644
--- a/av1/encoder/ethread.c
+++ b/av1/encoder/ethread.c
@@ -2042,7 +2042,7 @@
   }
 
   // Sort tiles in descending order based on tile area.
-  qsort(pack_bs_tile_order, num_tiles, sizeof(pack_bs_tile_order),
+  qsort(pack_bs_tile_order, num_tiles, sizeof(*pack_bs_tile_order),
         compare_tile_order);
 }