EHCI fix code and ixp4xx test.

USB ehci configuration parameter:

#define CONFIG_CMD_USB          1
#define CONFIG_USB_STORAGE      1
#define CONFIG_USB_EHCI
#define CONFIG_USB_EHCI_IXP4XX	1
#define CONFIG_EHCI_IS_TDI	1
#define CONFIG_EHCI_DESC_BIG_ENDIAN     1
#define CONFIG_EHCI_MMIO_BIG_ENDIAN     1
#define CONFIG_SYS_USB_EHCI_MAX_ROOT_PORTS 2
#define CONFIG_LEGACY_USB_INIT_SEQ      1

2 USB Device(s) found
       scanning bus for storage devices... 0 Storage Device(s) found
=> usb tree

Device Tree:
  1  Hub (1.5MBit/s, 0mA)
  |  u-boot EHCI Host Controller
  |
  |+-2  Mass Storage (12MBit/s, 100mA)
       Sony Storage Media 0C07040930296

=>

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