IXP465 board and I find some errors in the code. This
patch fix:
- descriptor initizialization (config, interface and endpoint
  must be one next-to the other when the USB_DT_CONFIG message
  is send.
- FIX little/endian bigendian (introduce the CONFIG_EHCI_DESC_BIG_ENDIAN
  and the CONFIG_EHCI_MMIO_BIG_ENDIAN)
- Introduce the linux version of the usb_config_descriptor and
  usb_interface descriptor. This descriptor does't contains
  u-boot extension.

Signed-off-by: Michael Trimarchi <trimarchimichael@yahoo.it>
Signed-off-by: Remy Böhmer <linux@bohmer.net>