message: Fix tiff Grey(16) support
diff: @@ -463,10 +463,7 @@ impl<R: Read + Seek> ImageDecoder for TIFFDecoder<R> {
  self.width as usize
  * self.height as usize
  * self.bits_per_sample.iter().count();
  - let mut result = match (self.bits_per_sample.iter()
  - .cloned()
  - .max()
  - .unwrap_or(8) as f32/8.0).ceil() as u8 {
  + let mut result = match self.bits_per_sample.iter().cloned().max().unwrap_or(8) {
  n if n <= 8 => DecodingResult::U8(Vec::with_capacity(buffer_size)),
  n if n <= 16 => DecodingResult::U16(Vec::with_capacity(buffer_size)),
  n => return Err(
  