nvme: add device name to warning in uuid_show()

This provides more context to users.

Old message:

[   00.000000] No UUID available providing old NGUID

New message:

[   00.000000] block nvme0n1: No UUID available providing old NGUID

Fixes: d934f984 ("nvme: provide UUID value to userspace")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>