USB: EHCI big endian data structures support (for 440EPx)

This patch adds support for the AMCC 440EPx EHCI controller whose
in-memory data structures and the registers are represented in big-
endian format.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>