os/Makefile.unix: remove duplicate prerequisite
remove duplicate prerequisite for include/arch/board target
@@ -346,7 +346,7 @@ include/arch: Make.defs
# Link the configs/<board-name>/include directory to include/arch/board
-include/arch/board: include/arch Make.defs include/arch
+include/arch/board: include/arch Make.defs
@echo "LN: include/arch/board to $(BOARD_DIR)/include"
$(Q) $(DIRLINK) $(TOPDIR)/$(BOARD_DIR)/include include/arch/board
