Add missing declarations for AltiVec functions, fixes the warnings:

swscale_template.c:1171: warning: implicit declaration of function ‘altivec_yuv2packedX’
swscale.c:1982: warning: implicit declaration of function ‘yuv2rgb_altivec_init_tables’
yuv2rgb.c:652: warning: implicit declaration of function ‘yuv2rgb_init_altivec’

Originally committed as revision 25319 to svn://svn.mplayerhq.hu/mplayer/trunk/libswscale

libswscale/swscale_internal.h

@@ -183,6 +183,13 @@ typedef struct SwsContext{
 SwsFunc yuv2rgb_get_func_ptr (SwsContext *c);
 int yuv2rgb_c_init_tables (SwsContext *c, const int inv_table[4], int fullRange, int brightness, int contrast, int saturation);
 
+void yuv2rgb_altivec_init_tables (SwsContext *c, const int inv_table[4],int brightness,int contrast, int saturation);
+SwsFunc yuv2rgb_init_altivec (SwsContext *c);
+void altivec_yuv2packedX (SwsContext *c,
+                          int16_t *lumFilter, int16_t **lumSrc, int lumFilterSize,
+                          int16_t *chrFilter, int16_t **chrSrc, int chrFilterSize,
+                          uint8_t *dest, int dstW, int dstY);
+
 char *sws_format_name(int format);
 
 //FIXME replace this with something faster