USB: usb-storage: merge ATAPI and QIC-157 protocol routines

This patch (as1174) merges usb-storage's QIC-157 and ATAPI protocol
routines.  Since the two functions are identical, there's no reason to
keep them separate.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>