Bring palette back to nextgenv2

It was removed by the master branch merge.

Change-Id: I4b2a524c9e052e41063359afcb4ba22bf78344cf

vp10/encoder/tokenize.h

@@ -57,6 +57,9 @@ void vp10_tokenize_sb_inter(struct VP10_COMP *cpi, struct ThreadData *td,
                             BLOCK_SIZE bsize);
 #endif
 
+void vp10_tokenize_palette_sb(struct ThreadData *const td,
+                              BLOCK_SIZE bsize, int plane,
+                              TOKENEXTRA **t);
 void vp10_tokenize_sb(struct VP10_COMP *cpi, struct ThreadData *td,
                      TOKENEXTRA **t, int dry_run, BLOCK_SIZE bsize);