zorro: Don't fill in dummy names in zorro_name_device()

If the device is not found in the database, it's not needed to fill in
a dummy name. The caller of zorro_name_device() has already taken care
of that to support CONFIG_ZORRO_NAMES=n.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>