drm/arcpgu: remove drm_encoder_slave

drm_encoder_slave is the old way to write bridge drivers, for i2c
bridges only. It's deprecated, and definitely should not be used in
new drivers. This has absolutely nothing to do with the new bridge
driver infrastructure implemented by drm_bridge.

What's even strange is that arcpgu doesn't even use any of this, it
really only wants a plain normal drm_encoder. Nuke all the surplus
real estate.

v2: Actually git add after compile testing ...

v3: Clarify commit message and stop including drm_encoder_slave.h.

Cc: Laurent Pinchart <[e-mail]>
Cc: Alexey Brodkin <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/arc/arcpgu_hdmi.c

···
  */
 
 #include <drm/drm_crtc.h>
-#include <drm/drm_encoder_slave.h>
+#include <drm/drm_encoder.h>
+#include <drm/drm_device.h>
 
 #include "arcpgu.h"
 

drivers/gpu/drm/arc/arcpgu_sim.c

···
  */
 
 #include <drm/drm_crtc_helper.h>
-#include <drm/drm_encoder_slave.h>
 #include <drm/drm_atomic_helper.h>
 
 #include "arcpgu.h"
···
 
 struct arcpgu_drm_connector {
 	struct drm_connector connector;
-	struct drm_encoder_slave *encoder_slave;
 };
 
 static int arcpgu_drm_connector_get_modes(struct drm_connector *connector)
···
 int arcpgu_drm_sim_init(struct drm_device *drm, struct device_node *np)
 {
 	struct arcpgu_drm_connector *arcpgu_connector;
-	struct drm_encoder_slave *encoder;
+	struct drm_encoder *encoder;
 	struct drm_connector *connector;
 	int ret;
 
···
 	if (encoder == NULL)
 		return -ENOMEM;
 
-	encoder->base.possible_crtcs = 1;
-	encoder->base.possible_clones = 0;
+	encoder->possible_crtcs = 1;
+	encoder->possible_clones = 0;
 
-	ret = drm_encoder_init(drm, &encoder->base, &arcpgu_drm_encoder_funcs,
+	ret = drm_encoder_init(drm, encoder, &arcpgu_drm_encoder_funcs,
 			       DRM_MODE_ENCODER_VIRTUAL, NULL);
 	if (ret)
 		return ret;
···
 		goto error_encoder_cleanup;
 	}
 
-	ret = drm_mode_connector_attach_encoder(connector, &encoder->base);
+	ret = drm_mode_connector_attach_encoder(connector, encoder);
 	if (ret < 0) {
 		dev_err(drm->dev, "could not attach connector to encoder\n");
 		drm_connector_unregister(connector);
 		goto error_connector_cleanup;
 	}
-
-	arcpgu_connector->encoder_slave = encoder;
 
 	return 0;
 
···
 	drm_connector_cleanup(connector);
 
 error_encoder_cleanup:
-	drm_encoder_cleanup(&encoder->base);
+	drm_encoder_cleanup(encoder);
 	return ret;
 }