drm/i915/dp_mst: Reuse intel_dp_handle_link_service_irq()
Use intel_dp_handle_link_service_irq() while handling an MST HPD IRQ,
instead of open-coding this.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260225164618.1261368-19-imre.deak@intel.com