drm/i915/bios: Document the mess around the LFP data tables

Document the fact that struct lvds_lfp_data_entry can't be used
directly and instead must be accessed via the data table pointers.

Also remove the bogus comment implying that there might be a
variable number of panel entries in the table. There are always
exactly 16.
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220504150440.13748-5-ville.syrjala@linux.intel.com

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

@@ -735,7 +735,7 @@ struct lvds_lfp_data_ptr {
 } __packed;
 
 struct bdb_lvds_lfp_data_ptrs {
-	u8 lvds_entries; /* followed by one or more lvds_data_ptr structs */
+	u8 lvds_entries;
 	struct lvds_lfp_data_ptr ptr[16];
 	struct lvds_lfp_data_ptr_table panel_name; /* 156-163? */
 } __packed;
@@ -769,6 +769,11 @@ struct lvds_pnp_id {
 	u8 mfg_year;
 } __packed;
 
+/*
+ * For reference only. fp_timing has variable size so
+ * the data must be accessed using the data table pointers.
+ * Do not use this directly!
+ */
 struct lvds_lfp_data_entry {
 	struct lvds_fp_timing fp_timing;
 	struct lvds_dvo_timing dvo_timing;