drm/i915/bios: Define VBT block 21 (EFP List) contents

Define the contents of VBT block 21 (EFP List). Specs are nowhere
to be found, but real world data suggests that each entry is just
the first four bytes of the EDID PnP ID structure.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240503122449.27266-23-ville.syrjala@linux.intel.comAcked-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -921,6 +921,21 @@ struct bdb_oem_custom {
 	struct oem_mode modes[];
 } __packed;
 
+/*
+ * Block 21 - EFP List
+ */
+
+struct efp_entry {
+	u16 mfg_name;
+	u16 product_code;
+} __packed;
+
+struct bdb_efp_list {
+	u8 num_entries;
+	u8 entry_size;
+	struct efp_entry efp[];
+} __packed;
+
 /*
  * Block 22 - SDVO LVDS General Options
  */