drm/udl: Replace drm_dev_unref with drm_dev_put

drm/udl: Replace drm_dev_unref with drm_dev_put

commit ac3b35f11a06964f5fe7f6ea9a190a28a7994704 upstream.

This patch unifies the naming of DRM functions for reference counting
of struct drm_device. The resulting code is more aligned with the rest
of the Linux kernel interfaces.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180926120212.25359-1-tzimmermann@suse.de
Signed-off-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>