drm/i915/display: Handle invalid fb_modifier in intel_fb_modifier_to_tiling

Lookup_modifier is returning INTEL_PLANE_CAP_TILING_4 on invalid
fb_modifier value. Use lookup_modifier_or_null in
intel_fb_modifier_to_tiling and return I915_TILING_NONE in case
lookup_modifier_or_null returns null.

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231203114840.841311-4-jouni.hogander@intel.com