Revert rev 1.129:

Revert rev 1.129:
When detaching devices when we suspend, we need to continue processing
command completion events.  So only return early in xhci_softintr() if
the controller is dead instead of dying.  This fixes USB suspend/resume
in Apple M1/M2.

ok mlarkin@, deraadt@
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The change does not only allow completion events to be processed but also
events that get processed by the drivers attached to this usb bus. As a
result I see a uvm panic on suspend in urtwn(4) which is triggered by a
bad rx eof.

OK kettenis@