ruby: banked cache array resource model

This patch models a cache as separate tag and data arrays.  The patch exposes
the banked array as another resource that is checked by SLICC before a
transition is allowed to execute.  This is similar to how TBE entries and slots
in output ports are modeled.

src/mem/ruby/system/SConscript

@@ -55,3 +55,4 @@ Source('RubyPortProxy.cc')
 Source('Sequencer.cc')
 Source('System.cc')
 Source('TimerTable.cc')
+Source('BankedArray.cc')