manual: sprinkle with some calls to MESSAGE

Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

docs/manual/manual.mk

@@ -18,7 +18,7 @@ $(1): $(1)-$(3)
 $(1)-$(3): $$(O)/docs/$(1)/$(1).$(4)
 
 $$(O)/docs/$(1)/$(1).$(4): docs/$(1)/$(1).txt $$($(call UPPERCASE,$(1))_SOURCES)
-	@echo "Generating $(5) $(1)..."
+	@$(call MESSAGE,"Generating $(5) $(1)...")
 	$(Q)mkdir -p $$(@D)
 	$(Q)a2x $(6) -f $(2) -d book -L -r $(TOPDIR)/docs/images \
 	  -D $$(@D) $$<