Makefile: Drop yq prerequisite from 'manifests' target

3dd23a9 (Makefile,manifests: Remove the PlatformOperators cluster
profile hacks, 2022-09-21, openshift#64) removed the final consumer.
Subsequently 39662d6 (switch to bingo for dependency management,
2023-10-13, openshift#95) removed some other related targets and the YQ
variable definition.  But this manifests prereq snuck through, until
this commit, where I'm removing it.

Makefile

@@ -66,7 +66,7 @@ RBAC_LIST = rbac.authorization.k8s.io_v1_clusterrole_platform-operators-manager-
 
 # Generate manifests e.g. CRD, RBAC etc.
 .PHONY: manifests
-manifests: generate $(YQ) $(KUSTOMIZE)
+manifests: generate $(KUSTOMIZE)
 	$(KUSTOMIZE) build config/default -o $(TMP_DIR)/
 	ls $(TMP_DIR)