xhci: add helper to stop endpoint and wait for completion

xhci: add helper to stop endpoint and wait for completion

Expose xhci_stop_endpoint_sync() which is a synchronous variant of
xhci_queue_stop_endpoint().  This is useful for client drivers that are
using the secondary interrupters, and need to stop/clean up the current
session.  The stop endpoint command handler will also take care of cleaning
up the ring.

Modifications to repurpose the new API into existing stop endpoint
sequences was implemented by Wesley Cheng.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Co-developed-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Link: https://lore.kernel.org/r/20240217001017.29969-11-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>