staging: usbip: replace the interrupt safe spinlocks with common ones.

On the client side, we have a virtual hcd driver, there actually no
hardware interrupts, so we do not need worry about race conditions
caused by irq with spinlock held. Turning off irq is not good for system
performance after all. Just replace them with a non interrupt safe
version.

Signed-off-by: Harvey Yang <harvey.huawei.yang@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>