Remove dead code

variable "stage" is not used after incrementing

Change-Id: Ide8e51aef34cb3dbad94150d5481f297f7f66dba
diff --git a/av1/common/av1_inv_txfm1d.c b/av1/common/av1_inv_txfm1d.c
index c6b386f..8d69efc 100644
--- a/av1/common/av1_inv_txfm1d.c
+++ b/av1/common/av1_inv_txfm1d.c
@@ -806,7 +806,6 @@
   av1_range_check_buf(stage, input, bf1, size, stage_range[stage]);
 
   // stage 7
-  stage++;
   bf0 = step;
   bf1 = output;
   bf1[0] = bf0[0];
@@ -1007,7 +1006,6 @@
   av1_range_check_buf(stage, input, bf1, size, stage_range[stage]);
 
   // stage 9
-  stage++;
   bf0 = step;
   bf1 = output;
   bf1[0] = bf0[0];