V4L/DVB (5573): Pvrusb2: kill unnecessary attribute->owner

V4L/DVB (5573): Pvrusb2: kill unnecessary attribute->owner

sysfs is now completely out of driver/module lifetime game.

After deletion, a sysfs node doesn't access anything outside sysfs
proper, so there's no reason to hold onto the attribute owners.

Note that often the wrong modules were accounted for as owners leading
to accessing removed modules.

This patch kills now unnecessary attribute->owner.

Note that with this change, userland holding a sysfs node does not
prevent the backing module from being unloaded.

For more info regarding lifetime rule cleanup, please read the following
message:
	http://article.gmane.org/gmane.linux.kernel/510293

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>