xhci: debugfs: Add virt endpoint state to xhci debugfs

xhci: debugfs: Add virt endpoint state to xhci debugfs

The ring data structure of each xHCI endpoint might stop sending
data due to the virt endpoint state.

Show the virt endpoint state within the endpoint context via debugfs
to facilitate debugging.

Co-developed-by: Xu Rao <raoxu@uniontech.com>
Signed-off-by: Xu Rao <raoxu@uniontech.com>
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20241106101459.775897-10-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>