drm/i915/skl: Adjust get_plane_config() to support Yb/Yf tiling

v2: Rebased for addfb2 interface and consolidated a bit. (Tvrtko Ursulin)
v3: Rebased for fb modifier changes. (Tvrtko Ursulin)
v4: Use intel_fb_stride_alignment instead of open coding. (Damien Lespiau)

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>