USB: chipidea: ci13xxx_imx: Remove sparse warning

Remove the following sparse warning:

drivers/usb/chipidea/ci13xxx_imx.h:22:25: error: dubious one-bit signed bitfield
drivers/usb/chipidea/ci13xxx_imx.h:22:25: error: dubious one-bit signed bitfield
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/ci13xxx_imx.h

@@ -19,7 +19,7 @@ struct usbmisc_usb_device {
 	struct device *dev; /* usb controller device */
 	int index;
 
-	int disable_oc:1; /* over current detect disabled */
+	unsigned int disable_oc:1; /* over current detect disabled */
 };
 
 int usbmisc_set_ops(const struct usbmisc_ops *ops);