drm/i915/bios: Define VBT block 252 (int15 Hook)

Declare that VBT block 252 is the "int15 hook". This is some
VBIOS only juju so don't bother with a full definition.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240503122449.27266-35-ville.syrjala@linux.intel.comAcked-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_vbt_defs.h

@@ -188,6 +188,7 @@ enum bdb_block_id {
 	BDB_COMPRESSION_PARAMETERS	= 56, /* 213+ */
 	BDB_VSWING_PREEMPH		= 57, /* 218+ */
 	BDB_GENERIC_DTD			= 58, /* 229+ */
+	BDB_INT15_HOOK			= 252, /* VBIOS only */
 	BDB_SKIP			= 254, /* VBIOS only */
 };