iomap: always run error completions in user context

iomap: always run error completions in user context

[ Upstream commit ddb4873286e03e193c5a3bebb5fc6fa820e9ee3a ]

At least zonefs expects error completions to be able to sleep.  Because
error completions aren't performance critical, just defer them to workqueue
context unconditionally.

Fixes: 8dcc1a9d90c1 ("fs: New zonefs file system")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20251113170633.1453259-3-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>