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>