Add makefile
random3.hex cosimulation test was failing.
Normally, these tests detect when all threads have suspended themselves and ends the simulation.  However, there are race conditions where there are pending memory transactions queued up in the L2 cache store FIFO or memory controller.  In this case, the data is not flushed out and the test fails because memory contents do not match.
The solution is to run 100 cycles after the processor has halted to ensure everything is flushed out.