snow: remove unused stub functions

w53_32_c() and w97_32_c() are defined as stubs when snow encoder is
disabled.  In this case, those functions are not referenced at all
and do thus not need to be defined.

Originally committed as revision 22448 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/snow.h

@@ -128,9 +128,6 @@ void ff_snow_inner_add_yblock(const uint8_t *obmc, const int obmc_stride, uint8_
 #if CONFIG_SNOW_ENCODER
 int w53_32_c(void *v, uint8_t * pix1, uint8_t * pix2, int line_size, int h);
 int w97_32_c(void *v, uint8_t * pix1, uint8_t * pix2, int line_size, int h);
-#else
-static int w53_32_c(void *v, uint8_t * pix1, uint8_t * pix2, int line_size, int h) {assert (0); return 0;}
-static int w97_32_c(void *v, uint8_t * pix1, uint8_t * pix2, int line_size, int h) {assert (0); return 0;}
 #endif
 
 void ff_spatial_dwt(int *buffer, int width, int height, int stride, int type, int decomposition_count);