drm/bridge: synopsys: dw-dp: fix error paths of dw_dp_bind

Fix several issues in dw_dp_bind() error handling:

1. Missing return after drm_bridge_attach() failure - the function
   continued execution instead of returning an error.

2. Resource leak: drm_dp_aux_register() is not a devm function, so
   drm_dp_aux_unregister() must be called on all error paths after
   aux registration succeeds. This affects errors from:
   - drm_bridge_attach()
   - phy_init()
   - devm_add_action_or_reset()
   - platform_get_irq()
   - devm_request_threaded_irq()

3. Bug fix: platform_get_irq() returns the IRQ number or a negative
   error code, but the error path was returning ERR_PTR(ret) instead
   of ERR_PTR(dp->irq).

Use a goto label for cleanup to ensure consistent error handling.

Fixes: 86eecc3 ("drm/bridge: synopsys: Add DW DPTX Controller support library")
Cc: stable@vger.kernel.org

Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://patch.msgid.link/20260102155553.13243-1-osama.abdelkader@gmail.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Author: osamakader

drivers/gpu/drm/bridge/synopsys/dw-dp.c

@@ -2062,33 +2062,41 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 	}
 
 	ret = drm_bridge_attach(encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
-	if (ret)
+	if (ret) {
 		dev_err_probe(dev, ret, "Failed to attach bridge\n");
+		goto unregister_aux;
+	}
 
 	dw_dp_init_hw(dp);
 
 	ret = phy_init(dp->phy);
 	if (ret) {
 		dev_err_probe(dev, ret, "phy init failed\n");
-		return ERR_PTR(ret);
+		goto unregister_aux;
 	}
 
 	ret = devm_add_action_or_reset(dev, dw_dp_phy_exit, dp);
 	if (ret)
-		return ERR_PTR(ret);
+		goto unregister_aux;
 
 	dp->irq = platform_get_irq(pdev, 0);
-	if (dp->irq < 0)
-		return ERR_PTR(ret);
+	if (dp->irq < 0) {
+		ret = dp->irq;
+		goto unregister_aux;
+	}
 
 	ret = devm_request_threaded_irq(dev, dp->irq, NULL, dw_dp_irq,
 					IRQF_ONESHOT, dev_name(dev), dp);
 	if (ret) {
 		dev_err_probe(dev, ret, "failed to request irq\n");
-		return ERR_PTR(ret);
+		goto unregister_aux;
 	}
 
 	return dp;
+
+unregister_aux:
+	drm_dp_aux_unregister(&dp->aux);
+	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(dw_dp_bind);