f2fs: clear FI_HOT_DATA correctly

This patch fixes to clear FI_HOT_DATA correctly in below path:
- error handling in f2fs_ioc_start_atomic_write
- after commit atomic write in f2fs_ioc_commit_atomic_write
- after drop atomic write in drop_inmem_pages

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.c

@@ -255,6 +255,7 @@ void drop_inmem_pages(struct inode *inode)
 	mutex_unlock(&fi->inmem_lock);
 
 	clear_inode_flag(inode, FI_ATOMIC_FILE);
+	clear_inode_flag(inode, FI_HOT_DATA);
 	stat_dec_atomic_write(inode);
 }