um: Remove ia64 cruft

That code is a relict from the early days of UML.
ia64 support was never completed nor worked.
Let's rip it out.

Signed-off-by: Richard Weinberger <richard@nod.at>

diff --cc arch/um/Makefile-ia64
Simple merge

diff --cc arch/um/sys-ia64/Makefile
Simple merge

diff --cc arch/um/sys-ia64/sysdep/ptrace.h
Simple merge

diff --cc arch/um/sys-ia64/sysdep/sigcontext.h
Simple merge

diff --cc arch/um/sys-ia64/sysdep/skas_ptrace.h
Simple merge

diff --cc arch/um/sys-ia64/sysdep/syscalls.h
Simple merge