usb: xhci: Fix potential memory leak in xhci_disable_slot()
xhci_disable_slot() allows the invoker to pass a command pointer
as paramenter. Otherwise, it will allocate one. This will cause
memory leak when a command structure was allocated inside of this
function while queuing command trb fails. Another problem comes up
when the invoker passed a command pointer, but xhci_disable_slot()
frees it when it detects a dead host.
This patch fixes these two problems by removing the command parameter
from xhci_disable_slot().