usb: host: xhci: plat: move mvebu init_quirk() to xhci_plat_setup()

xhci_plat_setup() is the rightful place for
xhci_mvebu_mbus_init_quirk(), so let's move it there
in order to make it simpler to get rid of
xhci_plat_type_is() later on.

Acked-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>