Nobody checks the error flag on isofs folios, so stop setting and
clearing it.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240420025029.2166544-14-willy@infradead.org>