staging: ozwpan: Add debounce time before unregistering.

staging: ozwpan: Add debounce time before unregistering.

Fixes following error caused during unloading driver.

[ 1127.542888] usb 5-1: USB disconnect, device number 2
[ 1127.542909] ozwpan ozwpan: remove, state 1
[ 1127.542933] usb usb5: USB disconnect, device number 1
[ 1127.618634] hub 5-0:1.0: hub_port_status failed (err = -19)
[ 1127.618647] hub_port_connect_change: 45 callbacks suppressed
[ 1127.618657] hub 5-0:1.0: connect-debounce failed, port 1 disabled
[ 1127.618668] hub 5-0:1.0: cannot disable port 1 (err = -19)

Signed-off-by: Rupesh Gujare <rupesh.gujare@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>