Updates for registers and stuff.

Updates for registers and stuff.

arch/alpha/ev5.cc:
    Update for copying IPRs.
arch/alpha/isa_traits.hh:
    Allow for misc register file to serialize.  Also add some register copying code.
cpu/cpu_exec_context.cc:
    Use ISA's function to copy registers.

--HG--
extra : convert_revision : 09fa3b2b1b229cbf3a34f69354953da2607c2a8f