kbuild: clean up link rule of composite modules

cmd_link_multi-link is used only for cmd_link_multi-m.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/Makefile.build

@@ -526,10 +526,8 @@ $($(subst $(obj)/,,$(@:.o=-objs)))    \
 $($(subst $(obj)/,,$(@:.o=-y)))       \
 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
 
-cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
-
 quiet_cmd_link_multi-m = LD [M]  $@
-cmd_link_multi-m = $(cmd_link_multi-link)
+cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
 
 $(multi-used-m): FORCE
 	$(call if_changed,link_multi-m)