f2fs: fix to check inline_data during compressed inode conversion

When converting inode to compressed one via ioctl, it needs to check
inline_data, since inline_data flag and compressed flag are incompatible.

Fixes: 4c8ff709

 ("f2fs: support data compression")
Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>