kbuild: Enable compile after localversion change

Last minute change to localversion patch were faulty.
filechk needs a valid '$^' file. In this case unused but make sure to supply one.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Makefile

@@ -813,7 +813,7 @@ define filechk_version.h
 	)
 endef
 
-include/linux/version.h: FORCE
+include/linux/version.h: $(srctree)/Makefile FORCE
 	$(call filechk,version.h)
 
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