usb: ohci-hcd: Remove some unused legacy code

At this point, the only user of ohci-hcd that also uses PCI is using DM,
so we can drop CONFIG_PCI_OHCI* usage.  No platforms set either of
CONFIG_SYS_USB_OHCI_BOARD_INIT or CONFIG_SYS_USB_OHCI_CPU_INIT so those
hooks can be removed as well.

Signed-off-by: Tom Rini <trini@konsulko.com>