drm/edid: make drm_edid_header_is_valid() accept void pointer

It will be useful to accept a struct edid *, but for compatibility with
existing usage accept void *.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/33fbe1615a3bd82112eaf4077bbb521793cbb91a.1648752228.git.jani.nikula@intel.com

drivers/gpu/drm/drm_edid.c

@@ -1580,13 +1580,15 @@ static const u8 edid_header[] = {
  *
  * Return: 8 if the header is perfect, down to 0 if it's totally wrong.
  */
-int drm_edid_header_is_valid(const u8 *raw_edid)
+int drm_edid_header_is_valid(const void *_edid)
 {
+	const struct edid *edid = _edid;
 	int i, score = 0;
 
-	for (i = 0; i < sizeof(edid_header); i++)
-		if (raw_edid[i] == edid_header[i])
+	for (i = 0; i < sizeof(edid_header); i++) {
+		if (edid->header[i] == edid_header[i])
 			score++;
+	}
 
 	return score;
 }

include/drm/drm_edid.h

@@ -578,7 +578,7 @@ int drm_add_modes_noedid(struct drm_connector *connector,
 void drm_set_preferred_mode(struct drm_connector *connector,
 			    int hpref, int vpref);
 
-int drm_edid_header_is_valid(const u8 *raw_edid);
+int drm_edid_header_is_valid(const void *edid);
 bool drm_edid_block_valid(u8 *raw_edid, int block, bool print_bad_edid,
 			  bool *edid_corrupt);
 bool drm_edid_is_valid(struct edid *edid);