When ohci-hcd is shutting down, call ohci_usb_reset reset ohci-hcd, the
root hub generate an interrupt, but ohci->rh_state is OHCI_RH_HALTED,
and ohci_irq ignore the interrupt, the kernel trigger warning "irq
nobody cared". ehci-hcd is first disable interrupts, then reset ehci.
This patch disable ohci interrupt before reset ohci.
The patch is tested at the arm cortex-a9 demo board.