drm/i915: Introduce the plane->min_alignment() vfunc

drm/i915: Introduce the plane->min_alignment() vfunc

Different hardware generations have different scanout alignment
requirements. Introduce a new vfunc that will allow us to
make that distinction without horrible if-ladders.

For now we directly plug in the existing intel_surf_alignment()
and intel_cursor_alignment() functions.

For fbdev we (temporarily) introduce intel_fbdev_min_alignment()
that simply queries the alignment from the primary plane of
the first crtc.

TODO: someone will need to fix xe's alignment handling

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/20240612204712.31404-4-ville.syrjala@linux.intel.com
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>