ARM: mx3/cpuimx35: mark otg_pdata and usbh1_pdata as maybe unused

This fixes

	arch/arm/mach-mx3/mach-cpuimx35.c:143: warning: 'otg_pdata' defined but not used
	arch/arm/mach-mx3/mach-cpuimx35.c:148: warning: 'usbh1_pdata' defined but not used

when USB_ULPI is not selected.

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