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/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 2e6071e..5de4157 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -127,7 +127,7 @@
 	unsigned		authorized_default:1;
 	unsigned		has_tt:1;	/* Integrated TT in root hub */
 
-	int			irq;		/* irq allocated */
+	unsigned int		irq;		/* irq allocated */
 	void __iomem		*regs;		/* device memory/io */
 	u64			rsrc_start;	/* memory/io resource start */
 	u64			rsrc_len;	/* memory/io resource length */