These are defined like the normal ISO C mem* routines although x86 happens
to return void by accident.  Fix isdn to not assume a return value.

Sent to the isdn list, but as usual I didn't get any reply.

The patch is from the Debian kernel package and really old.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>