Add a temporary workaround to the panic on boot with hub attached and

panic on hub detach bugs that have been reported.  This work around
detaches the device before deleting it.  This changes the detach order
from in-order to pre-order.  This avoids uhub's deleting the children
after its subdevs has been deleted.

This is only a workaround.  This leads to a strange condition in the
device tree where attached devices are children of detached ones.  I
really don't know what that's supposed to mean, but does violate my
sense of POLA.  Fortunately, the violation is short lived, which is
why I'm going ahead and committing the work around.

# We really need to consider life w/o the multiple nested layers of
# compatibility macros.  They make finding bugs like this *MUCH*
# harder.

Patch by: iadowse

MT5 before: next_release(5.3-BETA5) (unless someting better comes along)

sys/dev/usb/usb_port.h

@@ -422,6 +422,7 @@ typedef struct callout usb_callout_t;
 #define config_detach(dev, flag) \
 	do { \
 		free(device_get_ivars(dev), M_USB); \
+		device_detach(dev); \
 		device_delete_child(device_get_parent(dev), dev); \
 	} while (0);