btrfs: remove unused members from struct btrfs_encoded_read_private

The inode and file_offset members in struct btrfs_encoded_read_private
are unused, so remove them.

Last used in commit 7959bd44 ("btrfs: remove the start argument to
check_data_csum and export") and commit 7609afac ("btrfs: handle
checksum validation and repair at the storage layer").
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -9895,8 +9895,6 @@ static ssize_t btrfs_encoded_read_inline(
 }
 
 struct btrfs_encoded_read_private {
-	struct btrfs_inode *inode;
-	u64 file_offset;
 	wait_queue_head_t wait;
 	atomic_t pending;
 	blk_status_t status;
@@ -9927,8 +9925,6 @@ int btrfs_encoded_read_regular_fill_pages(struct btrfs_inode *inode,
 					  u64 disk_io_size, struct page **pages)
 {
 	struct btrfs_encoded_read_private priv = {
-		.inode = inode,
-		.file_offset = file_offset,
 		.pending = ATOMIC_INIT(1),
 	};
 	unsigned long i = 0;