kbuild: fix ia64 link

ia64 build failed like this:

  CC      init/version.o
  LD      init/built-in.o
  KSYM    .tmp_kallsyms1.o
ld: .tmp_kallsyms1.o: linking constant-gp files with non-constant-gp files
ld: failed to merge target specific data of file .tmp_kallsyms1.o
make: *** [vmlinux] Error 1

This was introduced when link of vmlinux was migrated to a script.
Add missing option to as to fix this.
Reported-by: Tony Luck <tony.luck@gmail.com>
Tested-by: Tony Luck <tony.luck@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/link-vmlinux.sh

@@ -78,8 +78,8 @@ kallsyms()
 		kallsymopt=--all-symbols
 	fi
 
-	local aflags="${KBUILD_AFLAGS} ${NOSTDINC_FLAGS}                     \
-		      ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
+	local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
+		      ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
 
 	${NM} -n ${1} | \
 		scripts/kallsyms ${kallsymopt} | \