drm/displayid: pass iter to drm_find_displayid_extension()

It's more convenient to pass iter than a handful of its members to
drm_find_displayid_extension(), especially as we're about to add another
member.

Rename the function find_next_displayid_extension() while at it, to be
more descriptive.

Cc: Tiago Martins Araújo <[e-mail]>
Acked-by: Alex Deucher <[e-mail]>
Tested-by: Tiago Martins Araújo <[e-mail]>
Cc: [e-mail]
Link: https://patch.msgid.link/383[e-mail]
Signed-off-by: Jani Nikula <[e-mail]>

drivers/gpu/drm/drm_displayid.c

···
 	return base;
 }
 
-static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,
-					      int *length, int *idx,
-					      int *ext_index)
+static const u8 *find_next_displayid_extension(struct displayid_iter *iter)
 {
 	const struct displayid_header *base;
 	const u8 *displayid;
 
-	displayid = drm_edid_find_extension(drm_edid, DISPLAYID_EXT, ext_index);
+	displayid = drm_edid_find_extension(iter->drm_edid, DISPLAYID_EXT, &iter->ext_index);
 	if (!displayid)
 		return NULL;
 
 	/* EDID extensions block checksum isn't for us */
-	*length = EDID_LENGTH - 1;
-	*idx = 1;
+	iter->length = EDID_LENGTH - 1;
+	iter->idx = 1;
 
-	base = validate_displayid(displayid, *length, *idx);
+	base = validate_displayid(displayid, iter->length, iter->idx);
 	if (IS_ERR(base))
 		return NULL;
 
-	*length = *idx + sizeof(*base) + base->bytes;
+	iter->length = iter->idx + sizeof(*base) + base->bytes;
 
 	return displayid;
 }
···
 		/* The first section we encounter is the base section */
 		bool base_section = !iter->section;
 
-		iter->section = drm_find_displayid_extension(iter->drm_edid,
-							     &iter->length,
-							     &iter->idx,
-							     &iter->ext_index);
+		iter->section = find_next_displayid_extension(iter);
 		if (!iter->section) {
 			iter->drm_edid = NULL;
 			return NULL;