otg_ulpi_create is defined in drivers/usb/otg/ulpi.c which depends on
CONFIG_USB_ULPI.  So protect its usage by the same symbol.  Moreover
mxc_ulpi_access_ops needs CONFIG_MXC_ULPI.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Valentin Longchamp <valentin.longchamp@epfl.ch>
Cc: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>