dmi-id: fix a memory leak in dmi_id_init error path

This patch adds a missing kfree(dmi_dev) in dmi_id_init error path.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>