USB: Move definitions from usb.h to usb/ch9.h

The functions:

usb_endpoint_dir_in(epd)
usb_endpoint_dir_out(epd)
usb_endpoint_is_bulk_in(epd)
usb_endpoint_is_bulk_out(epd)
usb_endpoint_is_int_in(epd)
usb_endpoint_is_int_out(epd)
usb_endpoint_is_isoc_in(epd)
usb_endpoint_is_isoc_out(epd)
usb_endpoint_num(epd)
usb_endpoint_type(epd)
usb_endpoint_xfer_bulk(epd)
usb_endpoint_xfer_control(epd)
usb_endpoint_xfer_int(epd)
usb_endpoint_xfer_isoc(epd)

are moved from include/linux/usb.h to include/linux/usb/ch9.h.
include/linux/usb/ch9.h makes more sense for these functions because they
only depend on constants that are defined in this file.

Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>