TX_64X64: Reduce cos bits further.

This is to keep the high range within 32 bits.

AV1FwdTxfm2d.CfgTest passes after this fix.

Change-Id: I2df463c4ec9260c544d68aad445b60cabe2b531b
diff --git a/av1/common/av1_fwd_txfm1d_cfg.h b/av1/common/av1_fwd_txfm1d_cfg.h
index b3c9d3d..1bfb5ac 100644
--- a/av1/common/av1_fwd_txfm1d_cfg.h
+++ b/av1/common/av1_fwd_txfm1d_cfg.h
@@ -117,7 +117,7 @@
 // cos bit
 static const int8_t fwd_cos_bit_col_dct_64[12] = { 13, 13, 13, 13, 13, 13,
                                                    13, 13, 13, 13, 13, 13 };
-static const int8_t fwd_cos_bit_row_dct_64[12] = { 13, 13, 13, 12, 11, 10,
+static const int8_t fwd_cos_bit_row_dct_64[12] = { 13, 13, 12, 11, 10, 10,
                                                    10, 10, 10, 10, 10, 10 };
 
 //  ---------------- row config fwd_dct_4 ----------------