drm/edid: Clean up errors in drm_edid.c

Fix the following errors reported by checkpatch:

ERROR: do not use assignment in if condition
Signed-off-by: chenxuebing <chenxb_99091@126.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240111063921.8701-1-chenxb_99091@126.com

drivers/gpu/drm/drm_edid.c

@@ -3610,7 +3610,8 @@ static bool mode_in_range(const struct drm_display_mode *mode,
 	if (!mode_in_vsync_range(mode, edid, t))
 		return false;
 
-	if ((max_clock = range_pixel_clock(edid, t)))
+	max_clock = range_pixel_clock(edid, t);
+	if (max_clock)
 		if (mode->clock > max_clock)
 			return false;