drm/i915/lnl: possibility to enable FBC on first three planes

In LNL onwards, FBC can be associated to the first three planes.
FBC will be enabled on planes first come first served basis
until the userspace can select one of these FBC capable planes
explicitly.

v2:
 - avoid fbc->state.plane check in intel_fbc_check_plane (Ville)
 - simplify plane binding register writes (Matt)
 - Update the subject to reflect that fbc can be enabled only in
   the first three planes (Matt)

v3:
 - use icl_is_hdr_plane(), use wrapper macro for plane binding
   register access, comments update and patch split (Ville)

v4:
 - update to the plane binding register access macro

Bspec: 69560
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230922133003.150578-2-vinod.govindapillai@intel.com