drm/mgag200: convert get modes to struct drm_edid

Convert mgag200_vga_connector_helper_get_modes() to use struct drm_edid
based functions directly.
Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/19a453c725fc27bd890f8fc73104f43a376dfce0.1704473654.git.jani.nikula@intel.com

drivers/gpu/drm/mgag200/mgag200_mode.c

@@ -14,13 +14,13 @@
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_damage_helper.h>
+#include <drm/drm_edid.h>
 #include <drm/drm_format_helper.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_print.h>
-#include <drm/drm_probe_helper.h>
 
 #include "mgag200_drv.h"
 
@@ -717,17 +717,23 @@ void mgag200_crtc_atomic_destroy_state(struct drm_crtc *crtc, struct drm_crtc_st
 int mgag200_vga_connector_helper_get_modes(struct drm_connector *connector)
 {
 	struct mga_device *mdev = to_mga_device(connector->dev);
-	int ret;
+	const struct drm_edid *drm_edid;
+	int count;
 
 	/*
 	 * Protect access to I/O registers from concurrent modesetting
 	 * by acquiring the I/O-register lock.
 	 */
 	mutex_lock(&mdev->rmmio_lock);
-	ret = drm_connector_helper_get_modes_from_ddc(connector);
+
+	drm_edid = drm_edid_read(connector);
+	drm_edid_connector_update(connector, drm_edid);
+	count = drm_edid_connector_add_modes(connector);
+	drm_edid_free(drm_edid);
+
 	mutex_unlock(&mdev->rmmio_lock);
 
-	return ret;
+	return count;
 }
 
 /*