drm/i915: Sanitize the power well names

Use the shortest descriptive name for all power wells for simplicity and
to use the same name for the same type of power wells on multiple
platforms.
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220414210657.1785773-7-imre.deak@intel.com