drm/i915: Add Pipe D cursor ctrl register for Gen12

Currently the offset for PIPE D cursor control register is missing in
i915_reg.h due to which the cursor plane cannot be enabled for Pipe D.
This also causes kernel Warning, when a user requests to enable cursor
plane for PIPE D for Gen 12 platforms.

This patch adds the CURSOR_CTL_D register in the i915_reg.h.

v2: Rebase

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111640


Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
[Lucas: remove extra blank line]
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1569310312-12313-1-git-send-email-ankit.k.nautiyal@intel.com