[PATCH] um: Add missing "FORCE" target when using if_changed

[Randy Dunlap]

'make ARCH=um' says:

../arch/x86/um/Makefile:44: FORCE prerequisite is missing

and adding "FORCE" there makes it be quiet, so do it.  :)

Fixes: e1f86d7b4b2a ("kbuild: warn if FORCE is missing for if_changed(_dep,_rule) and filechk")
Signed-off-by: Randy Dunlap <rdunlap at infradead.org>
Cc: Masahiro Yamada <masahiroy at kernel.org>
Cc: Michal Marek <michal.lkml at markovi.net>
Cc: Nick Desaulniers <ndesaulniers at google.com>
Cc: linux-kbuild at vger.kernel.org
Cc: Jeff Dike <jdike at addtoit.com>
Cc: Richard Weinberger <richard at nod.at>
Cc: Anton Ivanov <anton.ivanov at cambridgegreys.com>
Cc: linux-um at lists.infradead.org
Cc: x86 at kernel.org
---
 arch/x86/um/Makefile |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20211007.orig/arch/x86/um/Makefile
+++ linux-next-20211007/arch/x86/um/Makefile
@@ -40,7 +40,7 @@ $(obj)/user-offsets.s: c_flags = -Wp,-MD
 	-Iarch/x86/include/generated
 targets += user-offsets.s
 
-include/generated/user_constants.h: $(obj)/user-offsets.s
+include/generated/user_constants.h: $(obj)/user-offsets.s FORCE
 	$(call filechk,offsets,__USER_CONSTANT_H__)
 
 UNPROFILE_OBJS := stub_segv.o