drm/i915: Remove the aliasing of power domain enum values

Aliasing the intel_display_power_domain enum values was required because
of the u64 power domain mask size limit. This makes the dmesg/debugfs
printouts of the domain names somewhat unclear, for instance domain
names for port D are shown on D12+ platforms where the corresponding
port is called TC1. Make this clearer by removing the aliasing which is
possible after a previous patch converting the mask to a bitmap.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220414210657.1785773-15-imre.deak@intel.com