drm/i915: Rename skl+ scaler binding bits

Rename the scaler binding bits to match the spec more closely.
Also call the parameters 'plane_id' to make it a bit more clear
what to pass in.

v2: Don't break gvt

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230426135019.7603-4-ville.syrjala@linux.intel.com