kbuild: move objtool_args back to scripts/Makefile.build

Commit b1a1a1a09b46 ("kbuild: lto: postpone objtool") moved objtool_args
to Makefile.lib, so the arguments can be used in Makefile.modfinal as
well as Makefile.build.

With commit 850ded46c642 ("kbuild: Fix TRIM_UNUSED_KSYMS with
LTO_CLANG"), module LTO linking came back to scripts/Makefile.build
again.

So, there is no more reason to keep objtool_args in a separate file.

Get it back to the original place, close to the objtool command.

Remove the stale comment too.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 3efc984..17508c0 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -224,6 +224,16 @@
 endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
 
 ifdef CONFIG_STACK_VALIDATION
+
+objtool_args =								\
+	$(if $(CONFIG_UNWINDER_ORC),orc generate,check)			\
+	$(if $(part-of-module), --module)				\
+	$(if $(CONFIG_FRAME_POINTER),, --no-fp)				\
+	$(if $(CONFIG_GCOV_KERNEL)$(CONFIG_LTO_CLANG), --no-unreachable)\
+	$(if $(CONFIG_RETPOLINE), --retpoline)				\
+	$(if $(CONFIG_X86_SMAP), --uaccess)				\
+	$(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount)
+
 ifndef CONFIG_LTO_CLANG
 
 __objtool_obj := $(objtree)/tools/objtool/objtool