drm/i915: Simplify the DG1 power well descriptors

Simplify the definition of DG1 power wells by reusing the identical
RKL DDI/AUX descriptors.

This reorders the DG1 DDI/AUX vs. PW4/5 power wells, but this shouldn't
make a difference (it is the order on RKL and the DDI/AUX power wells
don't have a dependency on PW4/5).

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220414210657.1785773-12-imre.deak@intel.com