FROMLIST: objtool: Don't autodetect vmlinux.o

With LTO, we run objtool on vmlinux.o, but don't want noinstr
validation. This change requires --vmlinux to be passed to objtool
explicitly.

Bug: 145210207
Change-Id: Ibfd814126df6b3d1a52f5461f2e5aac1377b02c9
Link: https://lore.kernel.org/lkml/20201013003203.4168817-4-samitolvanen@google.com/
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

scripts/link-vmlinux.sh

@@ -106,7 +106,7 @@ objtool_link()
 	local objtoolopt;
 
 	if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
-		objtoolopt="check"
+		objtoolopt="check --vmlinux"
 		if [ -z "${CONFIG_FRAME_POINTER}" ]; then
 			objtoolopt="${objtoolopt} --no-fp"
 		fi