kbuild: Fix debugging leftover

So now check for commandline options actually works again.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/Makefile.lib

@@ -186,7 +186,7 @@ cmd_gzip = gzip -f -9 < $< > $@
 ifneq ($(KBUILD_NOCMDDEP),1)
 # Check if both arguments has same arguments. Result in empty string if equal
 # User may override this check using make KBUILD_NOCMDDEP=1
-_arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
+arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
 
 endif