Remove unused macro from PVQ code

Change-Id: Ic01ba6097a8fe865d2d7e156bd600e58b63814d1

av1/encoder/pvq_encoder.c

@@ -28,7 +28,6 @@
 #include "av1/encoder/pvq_encoder.h"
 #include "aom_ports/system_state.h"
 
-#define OD_PVQ_RATE_APPROX (0)
 /*Shift to ensure that the upper bound (i.e. for the max blocksize) of the
    dot-product of the 1st band of chroma with the luma ref doesn't overflow.*/
 #define OD_CFL_FLIP_SHIFT (OD_LIMIT_BSIZE_MAX + 0)