nvme: fix warn output about shared namespaces without CONFIG_NVME_MULTIPATH

Move the stray '.' that is currently at the end of the line after
newline '\n' to before newline character which is the right position.

Fixes: ce8d7861 ("nvme: warn about shared namespaces without CONFIG_NVME_MULTIPATH")
Signed-off-by: Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>