ia64 kvm fixes for O=... builds

* EXTRA_CFLAGS do not apply for *.S
* don't bother with symlinks to ../lib/mem*.S, just add ../lib/mem*.o
  to object list

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>