Fix get_bits_long to work with ALT_BITSTREAM_READER_LE.

Gives the same result as get_bits_long_le in vorbis.c instead
of some wild big-/little-endian mixture.

Originally committed as revision 6332 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/bitstream.h

@@ -725,8 +725,13 @@ static inline void skip_bits1(GetBitContext *s){
 static inline unsigned int get_bits_long(GetBitContext *s, int n){
     if(n<=17) return get_bits(s, n);
     else{
+#ifdef ALT_BITSTREAM_READER_LE
+        int ret= get_bits(s, 16);
+        return ret | (get_bits(s, n-16) << 16);
+#else
         int ret= get_bits(s, 16) << (n-16);
         return ret | get_bits(s, n-16);
+#endif
     }
 }