usb: Add in missing EHCI helpers.

Several of the EHCI glue drivers either predate or were merged in the
same timeframe as API changes at the USB core level, resulting in some
missing endpoint_reset and clear_tt_buffer_complete callbacks.

This fixes up all of ehci-atmel, mxc, w90x900, and xilinx-of to tie in
the new helpers, which brings them in line with everyone else.

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>