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

In the Linux kernel, the following vulnerability has been resolved:

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.