ext2: propagate errors from ext2_prepare_chunk

Propagate errors from ext2_prepare_chunk to the callers and handle them
there.  While touching the prototype also turn update_times into a bool
from the current int used as bool.

[JK: fixed up error recovery path in ext2_rename()]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230116085205.2342975-1-hch@lst.de>