usb: core: hcd: make hcd->irq unsigned

There's really no point in having hcd->irq as a
signed integer when we consider the fact that
IRQ 0 means NO_IRQ. In order to avoid confusion,
make hcd->irq unsigned and fix users who were
passing -1 as the IRQ number to usb_add_hcd.

Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 34b9edd..831fa40 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -899,7 +899,7 @@
 	ohci_usb_reset (ohci);
 	ohci_writel (ohci, OHCI_INTR_MIE, &ohci->regs->intrdisable);
 	free_irq(hcd->irq, hcd);
-	hcd->irq = -1;
+	hcd->irq = 0;
 
 	if (quirk_zfmicro(ohci))
 		del_timer(&ohci->unlink_watchdog);