drm/i915: Move intel_surf_alignment() into skl_univerals_plane.c

Now that all pre-skl platforms have their own .min_alignment()
functions the remainder of intel_surf_alignment() can be hoisted
into skl_univerals_plane.c (and renamed appropriately).

Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240612204712.31404-8-ville.syrjala@linux.intel.com