drm/rockchip: Delete unnecessary assignment for the field "owner"

The field "owner" is set by the core.
Thus delete an unneeded initialisation.

Generated by: scripts/coccinelle/api/platform_no_drv_owner.cocci
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/41e48fd3-f713-7225-1df2-3b1f4758f949@users.sourceforge.net