arm64: defconfig/distro.conf: Select USB configs

Select the USB2 and USB3 PHYs found in QCS404 and enable the necessary
configs for dynamically configure a USB ethernet device.

Set up a USB configuration with:

  mount -t configfs none /sys/kernel/config/
  cd /sys/kernel/config
  cd usb_gadget/
  mkdir g1
  cd g1/
  echo 0x1209 > idVendor
  echo 0x0001 > idProduct
  mkdir strings/0x409
  echo 0123456789 > strings/0x409/serialnumber
  echo Linaro Qualcomm LT > strings/0x409/manufacturer
  echo LT device > strings/0x409/product
  mkdir functions/ncm.usb0
  mkdir configs/c.1
  mkdir configs/c.1/strings/0x409
  echo CDC ECM > configs/c.1/strings/0x409/configuration
  ln -s functions/ncm.usb0 configs/c.1

Then bind this to the USB2 UDC by issuing:

  echo 78c0000.dwc3 > UDC

or, for USB3:

  echo 7580000.dwc3 > UDC

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>