get_base_ctx_set calls get_base_ctx_from_count_mag

Change-Id: I598b2057dff1cdbdcc0f1464850f773b7ca5a7ac
diff --git a/av1/encoder/encodetxb.c b/av1/encoder/encodetxb.c
index b00abb5..432e9be 100644
--- a/av1/encoder/encodetxb.c
+++ b/av1/encoder/encodetxb.c
@@ -323,16 +323,7 @@
   }
 
   for (i = 0; i < NUM_BASE_LEVELS; ++i) {
-    ctx_set[i] = (ctx_set[i] + 1) >> 1;
-
-    if (row == 0 && col == 0)
-      ctx_set[i] = (ctx_set[i] << 1) + mag[i];
-    else if (row == 0)
-      ctx_set[i] = 8 + (ctx_set[i] << 1) + mag[i];
-    else if (col == 0)
-      ctx_set[i] = 18 + (ctx_set[i] << 1) + mag[i];
-    else
-      ctx_set[i] = 28 + (ctx_set[i] << 1) + mag[i];
+    ctx_set[i] = get_base_ctx_from_count_mag(row, col, ctx_set[i], mag[i]);
   }
   return;
 }