drm/i915: Update plane alignment requirements for TGL+

Currently we still use the SKL+ PLANE_SURF alignment even
for TGL+ even though the hardware no longer needs it.
Introduce a separate tgl_plane_min_alignment() and update
it to more accurately reflect the hardware requirements.

v2: Don't screw up DPT+semiplanar 2MiB alignment

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/20240612204712.31404-9-ville.syrjala@linux.intel.com