usb: Drop device-model specific copy of usb_legacy_port_reset

usb: Drop device-model specific copy of usb_legacy_port_reset

The device-model usb_legacy_port_reset function calls the device-model
usb_port_reset function which is a 1 on 1 copy of the non dm
usb_legacy_port_reset and this is the only use of usb_port_reset in all
of u-boot.

Drop both, and alway use the usb_legacy_port_reset() version in
common/usb.c .

Also while at it make it static as it is only used in common/usb.c .

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Simon Glass <sjg@chromium.org>