USB: UHCI: fix IRQ race during initialization

USB: UHCI: fix IRQ race during initialization

This patch (as1644) fixes a race that occurs during startup in
uhci-hcd.  If the IRQ line is shared with other devices, it's possible
for the handler routine to be called before the data structures are
fully initialized.

The problem is fixed by adding a check to the IRQ handler routine.  If
the initialization hasn't finished yet, the routine will return
immediately.

Signed-off-by: Alan Stern <[email protected]>
Reported-by: Don Zickus <[email protected]>
Tested-by: "Huang, Adrian (ISS Linux TW)" <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>