Add proper prototypes in a header file for global code under
drivers/isdn/sc/.

Since the GNU C compiler is now able do tell us that caller and callee
disagreed about the number of arguments of setup_buffers(), this patch
also fixes this bug.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>