CONFIG_USB_XHCI_OMAP is enabled for host mode independent of CONFIG_USB_DWC3
which is meant for gadget mode only. We need enable/disbale_usb_clocks() for
host mode as well so provide for it.
Fixes: 09cc14f4bc ("ARM: AM43xx: Add functions to enable and disable USB clocks"
Signed-off-by: Roger Quadros <rogerq@ti.com>