[PATCH] DRM: fix up classdev interface for drm core

Current drm code doesn't work with userspace programs that listen only
to the kernel event netlink socket as it is trying to create its own dev
interface.  Turns out lots of code can just be deleted as the driver
core can do all of this work automatically for you.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>