USB: otg Kconfig: let USB_OTG_UTILS select USB_ULPI option

With CONFIG_USB_ULPI=y, CONFIG_USB<=m, CONFIG_PCI=n and
CONFIG_USB_OTG_UTILS=n, which is the default used for mx31moboard,
the build for all mx3 platforms fails because drivers/usb/otg/ulpi.c
where otg_ulpi_create is defined is not compiled.

Build error:
arch/arm/mach-mx3/built-in.o: In function `mxc_board_init':
kzmarm11.c:(.init.text+0x73c): undefined reference to `otg_ulpi_create'
kzmarm11.c:(.init.text+0x1020): undefined reference to `otg_ulpi_create'

This isn't a strong dependency as drivers/usb/otg/ulpi.c doesn't
use functions defined in drivers/usb/otg/otg.o and is only needed
to get ulpi.o linked into the kernel image.

Signed-off-by: Valentin Longchamp <valentin.longchamp@epfl.ch>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>