Cleaned up some of the Fault system.

Cleaned up some of the Fault system.

arch/alpha/ev5.cc:
    Commented out the intr_post function since it's not used. If this really -is- needed, it should be moved into the fault class.
arch/alpha/faults.cc:
arch/alpha/faults.hh:
    Moved the fault invocation code into the fault class fully, and got rid of the need for isA.
cpu/exec_context.cc:
cpu/exec_context.hh:
    Removed the trap function from the ExecContext. The faults will execute normally in full system mode, but always panic in syscall emulation mode.
cpu/ozone/cpu.hh:
cpu/simple/cpu.hh:
    Changed the execution context executing a fault to a fault executing on the execution context.
sim/faults.cc:
    If not in full system mode, trying to invoke a fault causes a panic.
sim/faults.hh:
    Removed the isA function.

--HG--
extra : convert_revision : 894dc8f0755c8efc4b7ef5a09fb2cf7373042395