usb: ohci: change the NUM_EDs from 8 to 32

For ohci, the maximam supported endpoint number is 32(in and out), and
now we have used (usb_pipeendpoint(pipe) << 1) to index the specified
endpoint descritor, usb_pipeendpoint(pipe) can reach 0xf, so we need
change the NUM_EDs from 8 to 32.

Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com>