Fixes for full-system call_pal instruction.

Fixes for full-system call_pal instruction.

arch/alpha/alpha_memory.cc:
    Rename md_mode_type to mode_type.
arch/alpha/ev5.cc:
    simPalCheck() only gets called on correct path now, so
    there's no need to test misspeculating().
arch/alpha/isa_desc:
    Get privileged call_pall detection right this time (I hope).
    ExecContext::simPalCheck() and Annotate::Callpal() are now
    called only on non-speculative executions... this should fix
    the bogus pal-call stats we've been seeing (since these are
    incremented in simPalCheck()).
    Also check for invalid call_pall function codes.

--HG--
extra : convert_revision : 465d6724884007d3fa066d14cd5e6db0cd3954e1