This factors out a bunch of non-generic system calls into i386-specific
code.  It also adds the x86_64-specific system calls.
A couple of generic system calls handlers are declared in sysdep-i386 because
x86 has no declarations for them, but x86_64 has incompatible ones.

Also splits out syscalls on behalf on UML/S390 from Bodo Stroesser
Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>