cdev: remove unneeded setting of cdev names

struct cdev does not need the kobject name to be set, as it is never
used.  This patch fixes up the few places it is set.


Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org>