xhci: fix debugfs register accesses while suspended

commit 735baf1b upstream.

Wire up the debugfs regset device pointer so that the controller is
resumed before accessing registers to avoid crashing or locking up if it
happens to be runtime suspended.

Fixes: 02b6fdc2 ("usb: xhci: Add debugfs interface for xHCI driver")
Cc: stable@vger.kernel.org # 4.15: 30332eee: debugfs: regset32: Add Runtime PM support
Cc: stable@vger.kernel.org # 4.15
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20230405090342.7363-1-johan+linaro@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>