usb: gadget: tegra-xudc: add port_speed_quirk

OTG port on Tegra194 supports GEN1 speeds when in device mode and GEN2
speeds when in host mode. dd port_speed_quirk that configures port to
GEN1/GEN2 speds, corresponding to the mode.

Based on work by WayneChang <waynec@nvidia.com>

Signed-off-by: Nagarjuna Kristam <nkristam@nvidia.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>