drm/kms: rip out drm_mode_connector_detach_encoder

It's only used by imx, and that one gets it wrong - there's no need
to deteach the encoder before removing it.

And really, neither current drm modesetting code nor all the userspace
we have can handle dynamic changes in the set of possible encoders for
a given connector. So let's just remove this before someone starts
doing something really nasty with it.

As a plus, one less kerneldoc comment to write.

Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_crtc.c

@@ -3506,21 +3506,6 @@ int drm_mode_connector_attach_encoder(struct drm_connector *connector,
 }
 EXPORT_SYMBOL(drm_mode_connector_attach_encoder);
 
-void drm_mode_connector_detach_encoder(struct drm_connector *connector,
-				    struct drm_encoder *encoder)
-{
-	int i;
-	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
-		if (connector->encoder_ids[i] == encoder->base.id) {
-			connector->encoder_ids[i] = 0;
-			if (connector->encoder == encoder)
-				connector->encoder = NULL;
-			break;
-		}
-	}
-}
-EXPORT_SYMBOL(drm_mode_connector_detach_encoder);
-
 int drm_mode_crtc_set_gamma_size(struct drm_crtc *crtc,
 				  int gamma_size)
 {

drivers/staging/imx-drm/imx-ldb.c

@@ -595,8 +595,6 @@ static int imx_ldb_remove(struct platform_device *pdev)
 		struct drm_connector *connector = &channel->connector;
 		struct drm_encoder *encoder = &channel->encoder;
 
-		drm_mode_connector_detach_encoder(connector, encoder);
-
 		imx_drm_remove_connector(channel->imx_drm_connector);
 		imx_drm_remove_encoder(channel->imx_drm_encoder);
 	}

drivers/staging/imx-drm/parallel-display.c

@@ -244,8 +244,6 @@ static int imx_pd_remove(struct platform_device *pdev)
 	struct drm_connector *connector = &imxpd->connector;
 	struct drm_encoder *encoder = &imxpd->encoder;
 
-	drm_mode_connector_detach_encoder(connector, encoder);
-
 	imx_drm_remove_connector(imxpd->imx_drm_connector);
 	imx_drm_remove_encoder(imxpd->imx_drm_encoder);
 

include/drm/drm_crtc.h

@@ -1082,8 +1082,6 @@ extern const char *drm_get_encoder_name(const struct drm_encoder *encoder);
 
 extern int drm_mode_connector_attach_encoder(struct drm_connector *connector,
 					     struct drm_encoder *encoder);
-extern void drm_mode_connector_detach_encoder(struct drm_connector *connector,
-					   struct drm_encoder *encoder);
 extern int drm_mode_crtc_set_gamma_size(struct drm_crtc *crtc,
 					 int gamma_size);
 extern struct drm_mode_object *drm_mode_object_find(struct drm_device *dev,