ARM: mx3/mx35_3ds: rename usb otg platform data variable name

Rename the variable holding the usb otg platform data to avoid clash
with usb host platform data variable.

usb_pdata -> usb_otg_pdata

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>