slight adjustment to coef band definition

This commit adjusted slightly the 4x4 coefficents band definition to
better classify coefficients with similar distributions and usages.
It helps derf set about .1%, it is alos slightly positive for std-hd
set, where 4x4 blocks are used less frequently.

The commit also removed a const array not in use.

Change-Id: I78d16905d4036641ec905b0c32c190c1def5b249

vp8/common/entropy.c

@@ -48,7 +48,7 @@ DECLARE_ALIGNED(16, const unsigned char, vp8_norm[256]) =
 };
 
 DECLARE_ALIGNED(16, cuchar, vp8_coef_bands[16]) =
-{ 0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7};
+{ 0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7};
 
 DECLARE_ALIGNED(16, cuchar, vp8_prev_token_class[MAX_ENTROPY_TOKENS]) =
 { 0, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0};
@@ -77,13 +77,6 @@ DECLARE_ALIGNED(64, const int, vp8_default_zig_zag1d_8x8[64]) =
     58, 59, 52, 45, 38, 31, 39, 46, 53, 60, 61, 54, 47, 55, 62, 63,
 };
 
-DECLARE_ALIGNED(16, const short, vp8_default_inv_zig_zag[16]) =
-{
-    1,  2,  6,  7,
-    3,  5,  8, 13,
-    4,  9, 12, 14,
-   10, 11, 15, 16
-};
 
 DECLARE_ALIGNED(16, short, vp8_default_zig_zag_mask[16]);
 DECLARE_ALIGNED(64, short, vp8_default_zig_zag_mask_8x8[64]);//int64_t

vp8/common/entropy.h

@@ -96,7 +96,6 @@ extern const vp8_prob vp8_coef_update_probs_8x8 [BLOCK_TYPES] [COEF_BANDS] [PREV
 struct VP8Common;
 void vp8_default_coef_probs(struct VP8Common *);
 extern DECLARE_ALIGNED(16, const int, vp8_default_zig_zag1d[16]);
-extern DECLARE_ALIGNED(16, const short, vp8_default_inv_zig_zag[16]);
 extern short vp8_default_zig_zag_mask[16];
 extern DECLARE_ALIGNED(64, const int, vp8_default_zig_zag1d_8x8[64]);
 extern short vp8_default_zig_zag_mask_8x8[64];//int64_t