arm, config: Exit with fatal error if using Ruby

Ruby on ARM is currently very experimental. Fail with a fatal error
that explains this to make sure users are aware of the limitations (it
doesn't actually work yet!).

Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>

configs/common/FSConfig.py

@@ -393,6 +393,11 @@ def makeArmSystem(mem_mode, machine_type, num_cpus=1, mdesc=None,
     if not ruby:
         self.system_port = self.membus.slave
 
+    if ruby:
+        fatal("You're trying to use Ruby on ARM, which is not working " \
+              "properly yet. If you want to test it anyway, you " \
+              "need to remove this fatal error from FSConfig.py.")
+
     return self