Add a generic implementation of the ipc demultiplexer syscall. Except for
s390 and sparc64 all implementations of the sys_ipc are nearly identical.

There are slight differences in the types of the parameters, where mips
and powerpc as the only 64-bit architectures with sys_ipc use unsigned
long for the "third" argument as it gets casted to a pointer later, while
it traditionally is an "int" like most other paramters. frv goes even
further and uses unsigned long for all parameters execept for "ptr" which
is a pointer type everywhere. The change from int to unsigned long for
"third" and back to "int" for the others on frv should be fine due to the
in-register calling conventions for syscalls (we already had a similar
issue with the generic sys_ptrace), but I'd prefer to have the arch
maintainers looks over this in details.

Except for that h8300, m68k and m68knommu lack an impplementation of the
semtimedop sub call which this patch adds, and various architectures have
gets used - at least on i386 it seems superflous as the compat code on
x86-64 and ia64 doesn't even bother to implement it.

[akpm@linux-foundation.org: add sys_ipc to sys_ni.c]
Signed-off-by: Christoph Hellwig
Cc: Ralf Baechle
Cc: Benjamin Herrenschmidt
Cc: Paul Mundt
Cc: Jeff Dike
Cc: Hirokazu Takata
Cc: Thomas Gleixner
Cc: Ingo Molnar
Reviewed-by: H. Peter Anvin
Cc: Al Viro
Cc: Arnd Bergmann
Cc: Heiko Carstens
Cc: Martin Schwidefsky
Cc: "Luck, Tony"
Cc: James Morris
Cc: Andreas Schwab
Acked-by: Jesper Nilsson
Acked-by: Russell King
Acked-by: David Howells
Acked-by: Kyle McMartin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds