build: skip dockit on IBMi

Author: sravani1510

Makefile

@@ -838,6 +838,10 @@ out/doc/api: doc/api
 # Using grouped targets (&:) so Make knows one command produces all outputs
 ifeq ($(OSTYPE),aix)
 # TODO(@nodejs/web-infra): AIX is currently hanging during HTML minification
+$(apidocs_html) $(apidocs_json) out/doc/api/all.html out/doc/api/all.json:
+	@echo "Skipping $@ (not currently supported by $(OSTYPE) machines)"
+else ifeq ($(OSTYPE),os400)
+# TODO(@nodejs/web-infra): IBMi is currently hanging during HTML minification
 $(apidocs_html) $(apidocs_json) out/doc/api/all.html out/doc/api/all.json:
 	@echo "Skipping $@ (not currently supported by $(OSTYPE) machines)"
 else