ppc: drop unused function dct_quantize_altivec()

This also allows dropping some PPC-specific ugliness from dsputil.[ch].

libavcodec/dsputil.c

@@ -130,9 +130,6 @@ void ff_init_scantable(uint8_t *permutation, ScanTable *st, const uint8_t *src_s
         int j;
         j = src_scantable[i];
         st->permutated[i] = permutation[j];
-#if ARCH_PPC
-        st->inverse[j] = i;
-#endif
     }
 
     end=-1;

libavcodec/dsputil.h

@@ -197,10 +197,6 @@ typedef struct ScanTable{
     const uint8_t *scantable;
     uint8_t permutated[64];
     uint8_t raster_end[64];
-#if ARCH_PPC
-                /** Used by dct_quantize_altivec to find last-non-zero */
-    DECLARE_ALIGNED(16, uint8_t, inverse)[64];
-#endif
 } ScanTable;
 
 void ff_init_scantable(uint8_t *, ScanTable *st, const uint8_t *src_scantable);