fix Support multiple input files in Makefile.service

This commit fix Makefile.service to support multiple
input files which was introdce in this patch
I5ffbb4fdc0f4c44a14cd5066c0e80e5a8cd8fece

Change-Id: If8dd7eff983f917789e28aa23358b303718cfe58
diff --git a/xos/genx/tool/Makefile.service b/xos/genx/tool/Makefile.service
index a465797..9fb96f4 100644
--- a/xos/genx/tool/Makefile.service
+++ b/xos/genx/tool/Makefile.service
@@ -10,7 +10,7 @@
 all: models.py
 
 models.py: $(xprotos)
-	$(XOSGEN) --attic attic --input $< --target $(DJANGO_TARGET) --output $@
+	$(XOSGEN) --attic attic --target $(DJANGO_TARGET) --output $@ $<
 
 .PHONY: all