ANDROID: tools/objtool: Pass CFLAGS to libsubcmd build via EXTRA_CFLAGS

The upstream fix is too invasive to backport so we take a similar
fix like http://aosp/2755768

Bug: 355379840
Change-Id: I50258052fbf0c4f8ace7007427037122b4fd02b0
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=cd955bdd
Signed-off-by: Tao Wu <[email protected]>
(cherry picked from commit 42e503e28698187142397240819ca7f97b4374fc)

tools/objtool/Makefile

@@ -59,7 +59,7 @@ $(OBJTOOL): $(LIBSUBCMD) $(OBJTOOL_IN)
 
 
 $(LIBSUBCMD): fixdep FORCE
-	$(Q)$(MAKE) -C $(SUBCMD_SRCDIR) OUTPUT=$(LIBSUBCMD_OUTPUT)
+	$(Q)$(MAKE) -C $(SUBCMD_SRCDIR) EXTRA_CFLAGS="${CFLAGS}" OUTPUT=$(LIBSUBCMD_OUTPUT)
 
 clean:
 	$(call QUIET_CLEAN, objtool) $(RM) $(OBJTOOL)