usb: sunxi: ohci: make ohci_t the first member in private data

ohci-hcd casts priv_data pointer to (ohci_t *), thus it must be
the first member in private data struct.

Fixes 831cc98b ("usb: sunxi: Simplify ccm reg base code")

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>