added a clean rule

Author: AnoudAlshnakat

Makefile

@@ -29,5 +29,6 @@ docs/semantics/main.pdf: docs/semantics/p4_defs.tex docs/semantics/main.tex docs
 clean:
 	rm -f docs/semantics/p4_defs.tex hol/p4Script.sml
 	cd hol && Holmake clean -r && cd p4_from_json && Holmake clean && cd validation_tests && Holmake clean
+	cd hol/policy_to_table && Holmake clean 
 
 .PHONY: default clean hol