drm/i915: Drop a few unwanted tabs from skl+ plane reg defines

A few extra tabs have snuck into the skl+ plane register bit
definitions. Remove them.

v2: Rebase

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/20240513170008.15338-1-ville.syrjala@linux.intel.com