blockd.h: remove unused CFL_* macros

Uses of CFL_SUB8X8_VAL_MI_SIZE and CFL_SUB8X8_VAL_MI_SQUARE were removed
in:
ccd7081c49 Remove RECT_TX_EXT/RECT_TX_EXT_INTRA flags

Bug: aomedia:3416
Change-Id: Idad36079a10222699a0b4cdc58d70f1e0f5f19c7
diff --git a/av1/common/blockd.h b/av1/common/blockd.h
index 46a3ec7..e7f1b6b 100644
--- a/av1/common/blockd.h
+++ b/av1/common/blockd.h
@@ -518,11 +518,6 @@
 
 /*!\cond */
 
-#if CONFIG_DEBUG
-#define CFL_SUB8X8_VAL_MI_SIZE (4)
-#define CFL_SUB8X8_VAL_MI_SQUARE \
-  (CFL_SUB8X8_VAL_MI_SIZE * CFL_SUB8X8_VAL_MI_SIZE)
-#endif  // CONFIG_DEBUG
 #define CFL_MAX_BLOCK_SIZE (BLOCK_32X32)
 #define CFL_BUF_LINE (32)
 #define CFL_BUF_LINE_I128 (CFL_BUF_LINE >> 3)