drm/bridge: analogix: Remove redundant checks on existence of bridge->encoder

The checks on the existence of bridge->encoder in the implementation of
drm_bridge_funcs::attach() is not necessary, as it has already been checked
in the drm_bridge_attach() function call by previous bridge or KMS driver.
The drm_bridge_attach() will quit with a negative error code returned if
it fails for some reasons, hence, it is guaranteed that the .encoder member
of the drm_bridge instance is not NULL when various bridge attach functions
are called.

Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-13-sui.jingfeng@linux.dev

drivers/gpu/drm/bridge/analogix/analogix-anx6345.c

@@ -528,11 +528,6 @@ static int anx6345_bridge_attach(struct drm_bridge *bridge,
 		return -EINVAL;
 	}
 
-	if (!bridge->encoder) {
-		DRM_ERROR("Parent encoder object not found");
-		return -ENODEV;
-	}
-
 	/* Register aux channel */
 	anx6345->aux.name = "DP-AUX";
 	anx6345->aux.dev = &anx6345->client->dev;

drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c

@@ -897,11 +897,6 @@ static int anx78xx_bridge_attach(struct drm_bridge *bridge,
 		return -EINVAL;
 	}
 
-	if (!bridge->encoder) {
-		DRM_ERROR("Parent encoder object not found");
-		return -ENODEV;
-	}
-
 	/* Register aux channel */
 	anx78xx->aux.name = "DP-AUX";
 	anx78xx->aux.dev = &anx78xx->client->dev;

drivers/gpu/drm/bridge/analogix/analogix_dp_core.c

@@ -1228,11 +1228,6 @@ static int analogix_dp_bridge_attach(struct drm_bridge *bridge,
 		return -EINVAL;
 	}
 
-	if (!bridge->encoder) {
-		DRM_ERROR("Parent encoder object not found");
-		return -ENODEV;
-	}
-
 	if (!dp->plat_data->skip_connector) {
 		connector = &dp->connector;
 		connector->polled = DRM_CONNECTOR_POLL_HPD;

drivers/gpu/drm/bridge/analogix/anx7625.c

@@ -2193,11 +2193,6 @@ static int anx7625_bridge_attach(struct drm_bridge *bridge,
 	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
 		return -EINVAL;
 
-	if (!bridge->encoder) {
-		DRM_DEV_ERROR(dev, "Parent encoder object not found");
-		return -ENODEV;
-	}
-
 	ctx->aux.drm_dev = bridge->dev;
 	err = drm_dp_aux_register(&ctx->aux);
 	if (err) {
@@ -2435,11 +2430,6 @@ static void anx7625_bridge_atomic_enable(struct drm_bridge *bridge,
 
 	dev_dbg(dev, "drm atomic enable\n");
 
-	if (!bridge->encoder) {
-		dev_err(dev, "Parent encoder object not found");
-		return;
-	}
-
 	connector = drm_atomic_get_new_connector_for_encoder(state->base.state,
 							     bridge->encoder);
 	if (!connector)