nvme: fix identify error status silent ignore

Commit 59c7c3ca intended to only silently ignore non retry-able
errors (DNR bit set) such that we can still identify misbehaving
controllers, and in the other hand propagate retry-able errors (DNR bit
cleared) so we don't wrongly abandon a namespace just because it happens
to be temporarily inaccessible.

The goal remains the same as the original commit where this was
introduced but unfortunately had the logic backwards.

Fixes: 59c7c3ca ("nvme: fix possible hang when ns scanning fails during error recovery")
Reported-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>