usb: chipidea: imx: set CI_HDRC_IMX28_WRITE_FIX for imx28

Due to imx28 needs ARM swp instruction for writing, we set
CI_HDRC_IMX28_WRITE_FIX for imx28.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>