Rework txk_type indexing system for chroma component

Use the row and column indexes to fetch txk_type, which allows the
chroma components to derive the tx type from the corresponding luma
components. It improves the coding performance of txk-sel by 0.18%.

Change-Id: I3f4bca5839e13ae95e51053e76cd86fe58202ac9
diff --git a/av1/decoder/decodemv.h b/av1/decoder/decodemv.h
index 9538e96..162cf32 100644
--- a/av1/decoder/decodemv.h
+++ b/av1/decoder/decodemv.h
@@ -37,7 +37,8 @@
                       int supertx_enabled,
 #endif
 #if CONFIG_TXK_SEL
-                      int block, int plane, TX_SIZE tx_size,
+                      int blk_row, int blk_col, int block, int plane,
+                      TX_SIZE tx_size,
 #endif
                       aom_reader *r);