erofs: avoid infinite loop due to incomplete zstd-compressed data

erofs: avoid infinite loop due to incomplete zstd-compressed data

Currently, the decompression logic incorrectly spins if compressed
data is truncated in crafted (deliberately corrupted) images.

Fixes: 7c35de4df105 ("erofs: Zstandard compression support")
Reported-by: Robert Morris <rtm@csail.mit.edu>
Closes: https://lore.kernel.org/r/50958.1761605413@localhost
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chunhai Guo <guochunhai@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>