Add missing include. Fix the following compiler warnings:

twinvq.c: In function 'decode_lsp':
twinvq.c:575: warning: implicit declaration of function 'ff_sort_nearly_sorted_floats'

Originally committed as revision 20594 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/twinvq.c

@@ -22,6 +22,7 @@
 #include "avcodec.h"
 #include "get_bits.h"
 #include "dsputil.h"
+#include "lsp.h"
 
 #include <math.h>
 #include <stdint.h>