[PATCH] move ioprio syscalls into syscalls.h

- Make ioprio syscalls return long, like set/getpriority syscalls.
- Move function prototypes into syscalls.h so we can pick them up in the
  32/64bit compat code.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>