Fix wrong conditional, Snow decoding, not encoding, was SIMD-accelerated.

Originally committed as revision 8116 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/i386/dsputil_mmx.c

@@ -3037,7 +3037,7 @@ static void float_to_int16_sse(int16_t *dst, const float *src, int len){
     asm volatile("emms");
 }
 
-#ifdef CONFIG_SNOW_ENCODER
+#ifdef CONFIG_SNOW_DECODER
 extern void ff_snow_horizontal_compose97i_sse2(DWTELEM *b, int width);
 extern void ff_snow_horizontal_compose97i_mmx(DWTELEM *b, int width);
 extern void ff_snow_vertical_compose97i_sse2(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2, DWTELEM *b3, DWTELEM *b4, DWTELEM *b5, int width);
@@ -3462,7 +3462,7 @@ void dsputil_init_mmx(DSPContext* c, AVCodecContext *avctx)
             c->avg_h264_chroma_pixels_tab[1]= avg_h264_chroma_mc4_3dnow;
         }
 
-#ifdef CONFIG_SNOW_ENCODER
+#ifdef CONFIG_SNOW_DECODER
         if(mm_flags & MM_SSE2){
             c->horizontal_compose97i = ff_snow_horizontal_compose97i_sse2;
             c->vertical_compose97i = ff_snow_vertical_compose97i_sse2;